Author's Note:
So back in the days of the FFML, there were these stories that were generally labeled as "Mystery Fusions", "Crossovers That Should Never Be", or some variant on that theme. In many respects, this story is actually a fall back to that model.

This story has a very bizarre premise that could be off putting (i.e. potential squick warning) and I was actually a bit leery of putting it out based on the response to another story I wrote recently and posted elsewhere. But ultimately, I figure my brain is what it is. We'll see how this one is received before I start hiding works in the shadows of my hard drive. :) (I will warn that there are love potions involved and while there are long term consequences, forced love isn't really one of them.)

I'm interested in whether people will actually manage to guess the crossover/fusion before it becomes blatantly obvious (to those who have seen the relevant source material anyway). I'm guessing not, but you never know.

oOoOooOoOooOoOo

"Hey, Evans." James smiled and ran his hair through his hair, though Lily only caught it from the edge of her vision. She sighed audibly and didn't respond, let alone turn to face him. She didn't particularly want to let Potter see her red rimmed eyes. Maybe he would actually go away for once if she ignored him.

Moments later, he had plopped down beside her though, disregarding her obvious wishes. She continued to pay him a complete lack of attention, her hair draped over the book she had in her lap as she pretended to read.

"Evaaans. Merlin, Evans, can you hold a grudge. It's been hours." His voice was amused, though there was a trace of something else in it too. "Look, I came up to apologize and all. See if I can make it up to you. Maybe dinner?"

She refused to answer. Refused to be baited as he continued to throw off lines and attempt to entice her into an argument or a kiss. He didn't seem to care which.

So he pulled her hair.

That. Was. It.

She whirled on him in a rage, her concerns about her eyes and the emotional distress they might give away ignored. The anger causing color to bloom on her cheeks would likely distract from that anyway and she didn't particularly care what James thought of her anyway now that she thought about it.

"What is wrong with you, Potter!" Her hands clenched and the only reason she didn't actually attempt to hex him was the fact that he had his bully boys standing behind him. Sirius and Peter, the only one with a modicum of sense in the bunch being suspiciously absent. "Are you five years old, trying to get my attention by pulling my pigtails?"

He gave that same casual grin and said, "Pigtails? You'd look smashing in those and I'll pull them anytime you'd like."

"How... What did you not get when I said you make me sick, you disgusting, arrogant twit?" Her voice nearly cracked and her eyes flashed as she tried to get control of her emotions, but this day had been too much. She had lost her closest friend and this boy had been the direct cause. Severus wouldn't have had to turn to those pureblood bigots if these idiots hadn't chased him to them with their ceaseless attacks for five years straight.

Leaning forward, she stared into his eyes, ignoring his friends and hissed, "I don't know how you got into Gryffindor because you are a cowardly, bullying prat who wouldn't know true courage if it punched you in the face."

"Love you, too, Evans."

She almost screamed, but reined in her temper finally. Closing her eyes, she took a deep breath and calmed herself. Opening them again, she stared at James Potter and he looked back expectantly as the other Marauders looked on.

Calmly, she said, "I would rather date the giant squid than spend one more minute in your presence, James. Leave me alone."

And she left.

ooOoo

Prongs had laughed it off, but Sirius had seen that last jab, delivered without the usual passion that drove Lily's insults, had hurt him. As their mate went back up the stairs to the boys dorms, Padfoot reached over and wrangled Peter before he could follow.

"Hey, Pete."

"Yeah?" Wormtail looked over at Sirius before glancing back at the two separate stairs that James and Lily had used to leave.

Sirius took a breath. This prank might be over the edge, but she really did deserve it after that harrangue. Prongs was a bit arrogant sometimes, but he was a good bloke. "You're good at potions, right? Think you can pull off Amortentia?"

Peter pulled in a sharp breath, then glanced around. "Are you nuts, Padfoot? There's no way James will go for that- if he was willing to resort to love potions he could brew them himself. Even Amortentia's not permanent anyway, it'll wear off in a few months."

"It's not for James." Sirius grinned maliciously. "I'm thinking we should take Evans at her word. See how she likes a little one-sided infatuation of her own."

Wormtail stared at him for a moment, then his eyes widened. "The... you're not serious, are you?" He giggled nervously, but Sirius could see the realization dawning even before he could reply.

"You should know by now, Pete. I'm always Sirius."

ooOoo

Closing her eyes, Lily cursed the cold that was going around yet again and looked down at the cloudy liquid swirling through the tea Marlene had brought her. Her nose was so stuffed up she couldn't smell what she was sure was a lovely scent, but it looked wonderful at least. It almost seemed to shine in the light and the steam wafted from the surface in a spiral. She could almost taste the tea just by breathing in that cloud despite her cold.

Putting it to her lips, she sipped then her eyes widened at the taste. This was... this was amazing. It was the best tea she had ever had by far. She had to ask Marlene for the recipe. She couldn't help herself and quickly drained the rest of the cup, then walked over to her friend.

"Marlene!" She shook her friends shoulder and the girl turned to her with a sleepy expression, raising her head from her pillow.

"Huh? What's up? Ready for that Pepper-Up Potion after all?"

Lily shook her head and held out the teacup. "No, I wanted to get your recipe for this tea. It was amazing, the best I've ever had- I kind of wanted more if you had it."

"I didn't make it. It was supposed to have come from the kitchens," Marlene said slowly, eyeing her as she drooped with dissappointment. She looked a bit concerned.

"Oh." Lily fought back the disappointment, but she grew a touch concerned at Marlene's next words.

"Sirius gave it to me. He said he had an in with the house elves."

ooOoo

Sirius grinned to himself as he watched Lily sneak out of the classroom yet again. Her friends had apparently lost track of her. Looking around quickly, he shifted into his dog form and followed her at a distance with a steady lope.

As expected, she soon made her way out of the castle and down to the lake. It was a lovely day and worth the trip, particularly as he saw the girl that had caused James so much heart break drop to the ground to stare out over the placid waters with a forlorn sigh.

Snickering to himself, Sirius thought that this was probably worth the week or more that James wouldn't speak to him. It was so entirely perfect that he found himself out here watching Lily more often than he probably should. Particularly given the number of detentions he had to serve out yet for the prank. He needed a break from those periodically and no one was going to expect him out here.

Truth be told, after a month of escaping to watch Lily recite surprisingly good poetry to the giant squid, he could almost see what James saw in her. Her one sided monologues were surprisingly witty and amusing. He had no doubt that when the potion wore off, he was going to receive the hexing of his life based on how easily she evaded her handlers, but it had all been in good fun.

A ward around the lake, raised by Flitwick or Dumbledore, prevented anyone from entering the waters, so his prank had turned out almost exactly how he'd hoped. Well, aside from the fact that he had single handedly shut down the swimming season for Hogwarts. That hadn't made him a lot of friends.

He was enjoying just laying about in the sun and listening to Lily's voice when his eyes snapped open as she finished a line and then said, "Petrificus Totalus!" He was far to late to actually respond to the spell in time though and found himself stiff as a board, watching Lily as she lowered her wand with a quick smile and then busied herself with something she had apparently been working on at the edge of the water.

She worked quickly and it wasn't long before an odd sound filled the air. To his complete lack of surprise, the noises summoned the giant squid from the depths and he was treated to the rather disquieting sight of Lily pressing herself against the wards. Disquieting in this case because she was apparently planning something, had known he was here, and he had no doubts was prepared to deal with those wards in some manner.

ooOoo

Lily stared at her stomach with oddly mixed feelings. Fear. Wonder. A surprising lack of disgust. There was nothing visible, but despite the fact that it was too early by far she was certain she could actually feel the baby kicking. Could actually feel the baby's magic intertwining with her own.

The Amortentia had worn off earlier this week to the general rejoicing of her friends and she had taken the time to put Sirius into the Hospital Wing, something he had accepted with an unusually serious expression and a complete lack of resistance. Twice.

Her memories of the last couple months were... fuzzy.

However, she remembered a rough outline. She had understood her feelings were magically induced, but they had been stronger than anything she had ever felt prior to that. And she had come up with a plan to keep something of her "love". She had been surprisingly sneaky, enough that she wondered if she wouldn't have gone to Slytherin along with Severus if it weren't for their contempt for muggleborns.

There had been trips to the Restricted Section of the library, theft from Slughorn's supplies, and she was fairly certain she had uncovered the fact that Sirius Black was an unregistered Animagus and blackmailed him with it.

The end result was... this. She laid a hand over her stomach and wondered if it was a remnant of the Amortentia that was generating the concern and care she felt for the baby. She had never actually been within 100 feet of the giant squid, but despite the lack of details, she was certain the baby was tied to it. She should be feeling sick from the thought.

Certainly everyone else would be if they found out. Amortentia or no, this was... The squid was an intelligent magical being, but she had never heard of wizarding kind cross breeding with anything other than humanoids like the goblins or giants like Hagrid's mother.

And even in those cases the children and their parents were typically shunned.

Her thoughts were interrupted by the sound of the door opening and she quickly pulled her robes shut again and spun, her wand out. When Sirius stepped through the doors she almost started casting again then and there, but his expression and the fact that he had his hands up to show he wasn't holding his wand checked her actions.

"I just want to talk," Sirius said. He had a hangdog expression on his face, the thought of which almost sent her into hysterical giggles when she remembered his Animagus form, and was generally speaking more serious looking than she had ever seen. With the possible exception of when she had attacked him in a fury earlier in the week.

She gestured sharply with her wand and said, "Fine, talk."

"First. I wanted to apologize," he said, dropping his hands to his sides. "It wouldn't have meant anything to you while the potion was still in your system, but... I did want to say I'm sorry. Whatever that is worth." He shrugged and his robes wavered a bit- she thought he might have lost weight. His face and cheek bones were a little more well defined and his robes didn't fit quite as well as they normally did.

She made a noncommital noise in response to the apology and he just nodded slightly, like he wasn't expecting anything more.

"Second, I wanted to let you know that... well, I've seen you slipping away. And I think I know why. I was there after all. I don't expect you want to talk about it, but I'm here if you do." That elicited another moment of rage for her, but he didn't stop talking so she didn't have a chance to lay into him for the presumption. "I did some more research on Amortentia in the last month or so and realized just how badly I messed up."

He took a deep breath and then looked up, his silvery gray eyes meeting and locking with hers before continuing. "See, the 'Love Potion' wasn't really designed for its most common use. Everyone knows it doesn't create real feelings of love and that's true. That's mainly because it was intended to fascilitate cross-breeding of magical creatures though."

Her breath caught and he paused, apparently at a bit of a loss. He scrubbed a hand through his hair and slumped back against the wall. "I was stupid. Really, really stupid. I wanted you to feel a bit of what James feels when you shoot him down so hard. I can't stress enough how stupid I was. I resented what you were doing to him, but I still didn't want to put you in a situation where you could be taken advantage of- so when you made that comment... Well, the plan just kind of gelled in my mind."

"Comment?" She wasn't sure why she cared, but the question had slipped out.

Sirius barked out a self-deprecating laugh. "Should have known you wouldn't remember. You said, 'I would rather date the giant squid, than spend time with you'. Or something like that anyway, I don't really remember exactly myself. It was the same stuff you're always saying, just a touch meaner."

He shrugged again, his eyes still on the ground. "So anyway, I thought... why not do that. She'll feel the whole one-sided infatuation thing, we all get a laugh, and nothing happens. Except it did and it lasted longer than I expected since we only gave you a fraction of dose." He sighed. "I don't know for sure what that ritual you performed that day did, but after reading up on Amortentia after the threats you made I can guess."

Lily let out the bitter laughter that welled up at this turn of events. It wasn't funny exactly, but probably the last person she really wanted to know about this and he had actually seen her and put the dots together. It wasn't until she felt the tears drop onto her hands that she realized she was crying now and she looked up to see Sirius looking surprisingly helpless.

Taking a deep breath, she let it out and then said the words that she had been avoiding since the potion faded away. "You're right. I'm pregnant."

Getting the words out was like pushing a lead weight off of her chest. Sirius wasn't surprised though and just nodded. No overt signs of disgust or horror, though perhaps he had gotten that out of the way earlier. He had certainly had time.

"I have a plan for that." She blinked, startled. She hadn't expected anything from Sirius, let alone actual input. She had been honestly surprised to hear him apologize and him making amends somehow was the furthest thing from her mind.

She was tempted to throw his words back in his face, but... She had been flailing with this problem for a week and hadn't come up with a solid plan to avoid ruining her life. She couldn't stomach the thought of getting rid of the baby, but she was only 16. This, combined with her muggleborn status... it would ruin her. She would never be accepted in Wizarding society.

There was silence for a minute as he let her grapple with it, but she finally said, "I'm listening."

ooOoo

Sirius took a deep breath as he stepped onto the island of Azkaban, flanked by two Aurors. The place was depressingly gray and he suspected this was the nice part. The clouds above were slate gray and the sea a grey-ish blue that screamed "cold". The island itself was a dark gray that was almost black and maybe forty or fifty degrees at best during the summer. He understood it would be bitingly cold during the winter.

He shouldn't be here then, but that was only because of Lily Evans.

The use of Amortentia was not illegal and his detentions had been the extent of his punishment at Hogwarts and under the law for the prank he played on the muggleborn witch. When he confessed to actually using the Amortentia to make her infatuated with himself and using the "giant squid thing" as a convenient foil to hide their activities... Well, that was another thing altogether. Particularly with his having gotten her pregnant.

He was quite certain that James would never speak with him again. And the disgust on the face of Remus probably indicated the same there. Peter would keep his mouth shut, since he was the one who actually brewed the potion.

All told, his plan had gone off smashingly. And he had expected to spend the next two years of his life rotting in Azkaban with his wand snapped. It made it possible for Lily to get the potions she needed to delay the pregnancy safely though, since she had said she wasn't interested in ending it. He had some money coming from his Uncle that would let her deliver out of sight after she graduated and keep the baby hidden as well.

It had been a good plan and went off as flawlessly as any of the pranks he planned up until the sentencing. When Lily had actually pled for leniency for him and claimed she wanted him around for his child, that she had been impressed by the responsibility he showed and felt he had learned a valuable lesson. Her words had gotten him a reduced sentence that amounted to an entire summer spent in Azkaban and heavy parole restrictions after.

His pranking days at Hogwarts were done if he didn't want to return to this wonderful little vacation spot in the future. He couldn't say it was a bad trade off though.

ooOoo

Lily took a certain vindictive pleasure in crushing the hand that was in her own with all of her strength. With all of the advantages that magic had to offer, she couldn't believe that simple pain killers during birth were unavailable.

Healing potions, it turned out, were generally not safe for most children and especially for the unborn. And most wizarding logic agreed that the same applied to muggle drugs. There had been actual studies on how they contributed to the potential for Squib status by Arithmancers.

It had made for a miserable two years without the wonderful cure for the common cold that was Pepper-Up Potion. It turned out that 5 years of magical cure alls left your immune system woefully unprepared for reality.

Her child was going to have enough problems, though. She didn't need to take his magic away as well. So instead, she would handle this excruciating, mind-numbing pain the old fashioned way. By making sure the man responsible for it was in as much pain as she could manage when the contractions hit.

She glanced up at Sirius and wondered slightly at the changes two years could make in a man. Sirius had demonstrated a level of responsibility and maturity after he returned from his imprisonment that had frankly astonished her. Not that he didn't still joke and have the same dark sense of humor that had gotten him in trouble, but he kept it contained.

He had, in many ways, replaced Severus as her best friend when he returned.

While he felt he owed her what he had sacrificed, she had understood that he could have gotten away with doing nothing at all. And she had felt gratitude. It had grated on her since he was in large part responsible in the first place and she had taken that out on him by picking fights. And, guilt or not, Sirius Black was not one to back down from a challenge. Their arguments had annoyed their room mates and most of Gryffindor, but by the time they both backed down she had felt more comfortable with Sirius than most of the other 6th years.

She blamed that feeling of being indebted to him for confusing her so she decided she would give him what he wanted and date James Potter. That would be sufficient payment, particularly if she could repair the friendship that Sirius had lost in the process.

By Christmas break she was done with that and as it turned out, so was James, because he broke up with her. She hadn't seen that coming honestly, but it was mostly amiable and they ended as friends. It hadn't quite worked as she wanted it to anyway. Sirius and James were closer, but the dog Animagus had been peevish the entire time she had been dating his friend.

Accepting that she would just have to let her emotions do what they would, she had moved on. And eventually, they ended up here. Where she wasn't inflicting nearly enough-

Abandoning the attempts to distract herself with memories of the past, Lily concentrated on the labor. She supposed she should be lucky that size was apparently not a simple mix of the parents, but certainly her son had to be bigger than the average child. There was no way this could possibly be-

With a sudden sense of relief, her last contraction pushed her baby out and the midwife, paid well for her silence, wrapped him in a towel. Lily was rather worried that she hadn't heard a cry, but it was only minutes later that her child was handed to her.

Glancing over at Sirius, she smiled wanly when he squeezed her hand again then looked down to take in her son's appearance. Her first impression was that he was jaundiced... except that it wasn't a standard yellow. His face was a bright, bright yellow... which was actually fading to a pink color as she watched. He didn't appear to have a nose that she could see and his head was rounder than a human's, but she could feel his body underneath the towel and his little arms and legs.

Though... she blinked. Pulling open the towel, she noted that in addition to two arms that looked almost boneless her child had a few more legs than he probably should. With almost the same appearance as his arms, albeit missing the odd looking hands.

"All told, not bad really," Sirius finally said, when she had been quiet for too long. "He's a little unusual, but he's got two legs, two arms, and a head, right?" He grinned at her. "Plus a few spares."

She laughed and leaned down to kiss her baby on the head. He gurgled back at her and opened his little eyes, then wrapped one yellow "finger" around her own. His mouth opened up into a very wide happy smile and she felt the same love and affection that she had since she had first found out she was pregnant still welling up inside of her.

"Yes, you're right. He's perfect." She glanced up at Sirius with an arched eyebrow. "Are you sure that you're okay with naming him Harry? Won't that raise eyebrows given that he is supposed to be a Black and you are all forced to be named after stars and constellations?"

He shrugged and said, "Not like I don't rebel in every other area of the Black family standards. Plus, I found a way around that. Harry will be named after the Harry Roche Constellation."

Lily found her forehead wrinkling and she looked at Sirius in puzzlement. "I've never heard of that, where is it located in the sky?"

Sirius grinned and summoned something flat from across the room. Holding it up, she noted it was a muggle album. She groaned when she read the name. "Really, Sirius?"

"Siriusly," he replied, laughing at his own joke. "Besides, you're letting me choose his middle name and name him after my best mate. It's the least I can do."

"The very least," she added dryly.

ooOoo

As he barreled down on the house on the outskirts of London, Sirius cursed himself for the fiftieth time that night. He revved the engine of the motorcycle he was riding through the sky and shot forward at a pace far exceeding what he could have managed on a road. Far exceeding safe speeds in truth.

However, Peter hadn't been in the safe house they had established. There was no reason for him to have left, which meant that Lily and Harry were at risk.

When he saw the house, his mouth went dry though and he only just managed not to lose control of his ride.

The house was completely obliterated.

There was literally nothing but a pile of debris left.

He didn't know how he made it down to the ground, but when he finally shook off some of his shock he found himself staring at the remains of the house from his knees, tears streaming down his cheeks. Pushing himself to his feet, he staggered for a moment and then moved towards the back of the house.

He had to at least check... had to see for himself. He pulled out his wand and started banishing and summoning the debris, anything to get it out of the way so he could get to Harry's room. It was almost time to put him down to bed when he had left, he should have been there.

It was only a few minutes later that he caught his breath- the last beam he had shifted had revealed a blue glow. The glow of a shield. He redoubled his efforts and ran for the shield as soon as the last of the housing materials had been banished. He was fairly certain that he had put that one through the house next door, but he didn't care so long as-

The shield flickered and fell and Sirius found himself on his knees again, though this time in relief. Lily's wand arm dropped to her side and she flopped backwards, exhausted. He scrambled forward and found her holding little Harry, who was looking very pleased with himself and very yellow and tentacly again.

"What happened?" It was all he could get out as he looked around the disaster and back to the pair lying unharmed in the middle of it all.

Lily let out a weak little laugh, still panting from the effort of holding the shield against the debris from their house. She dropped her wand though and hugged Harry to her, who in turn hugged her with all ten tentacles.

"Harry happened," she finally said, her eyes resting fondly on her son.

"Harry?"

She nodded. "Yes, well, and Voldemort."

"Voldemort was here!?" Sirius jumped to his feet again, spinning to scan the shadows.

"Sirius! You don't need to worry, he's gone. He's dead."

Turning his gaze back to Lily, Sirius just gaped. She smiled mischievously and said, "Harry did it... I thought we were done, I had prepared... well, it doesn't matter. When Voldemort showed up, I ran for Harry though and prepared myself to stop him any way I could."

She gazed down fondly at her son, who was turning pink again as he apparently settled into sleep despite the awkward position. "When Voldemort finally made it to his room though, he threatened me first. That actually set off Harry and he... well, he apparently broke the blood adoption and resumed his real form. I've never seen anyone move as fast as he did and he just blew Voldemort away."

"Unfortunately, he also blew away most of the support structure for the house and it collapsed," she added dryly. "I just barely got up a shield and... well, then you showed up." She smiled at him.

"That..." Sirius was speechless. Voldemort was gone, killed by Harry. Who... also had shed the form the blood adoption that Sirius had performed had given him. That was going to be a problem. They would work around it though- you couldn't adopt someone twice, so maybe if James did it... They would need to bring him in on the truth, but he was sure they could trust him.

Looking at the little yellow guy he called his son, Sirius pushed the thoughts away though and knelt down to pull both Lily and Harry into the tighest hug he could manage. They could deal with the rest later, for now he was just going to savor the fact that his family was safe.

oOoOooOoOooOoOo

Author's Notes:
So, yes, in this fic, the power that Voldemort knows not is the ability to move at Mach 20. :) Harry James Potter (after the blood adoption) is or will be Koro-sensei eventually. And is, of course, the son of Lily Evans and the giant squid. (For those not familiar with the anime or manga, Koro-sensei is from Assassination Classroom.)

This turned out a lot longer than I was really planning and oddly almost ended up being more about a Lily and Sirius pairing (whether best friends or potentially romantic, I never really decided myself) than it did about the original premise. Which was solely me reading a line not unlike the one in this fic: "I would rather date the giant squid than you, James Potter".

That prompted unfortunate thoughts and this is ultimately the end result.

For the moment, I'm marking this as complete, but it could potentially see an epilogue with Koro-sensei and his classroom at some point.