A/N: Warning: This is actually pretty dark. Try not to think about it too much...

They're Slipping...

Originally, Dr. Horrible had just been a concept. Billy had always loved science as far back as he could remember, and he needed a friendly desperately. That was how Dr. Horrible was, well, born for lack of a better word.

The world was a terrible place, even to tiny Billy, and he wanted someone to fix it and help everybody. Dr. Horrible, his best and only friend, was just so smart it seemed like a good idea. (They were both smart, but Billy was far too shy to ever do anything...) Dr. Horrible just... kind of became a mad scientist of his own accord. He wasn't really evil, but he had a lot more confidence than Billy and he was a lot less friendly.

The first time Dr. Horrible had really been there was that night. Billy didn't remember much of the event other than the bad man coming to the house and the police sirens screaming outside as he sits in the cold liquid trying to get Mommy to just wake up-

Basically, Dr. Horrible had taken over for him.

Billy didn't know it at the time, of course. What with being moved into the orphanage since nobody wanted him, and having to transfer schools and helping sell everything he didn't want in his house. He spent a lot of time crying, wondering why he couldn't go home anymore because he just couldn't remember what had happened.

The first time Billy met Dr. Horrible, he was sitting in class. It felt like Billy was slowly being dragged away from his body, kind of like falling asleep. Everything was dark for a moment, but he still felt some kind of awareness. Where was he? What was happening?

He had woken up a few minutes later. He looked around slowly, still confused. Billy decided to let go of it, maybe he really had been sleeping, when he looked down at his little white board. In messy hand-writing that was most definitely not his own, words were written, "Hello how are you Billy?"

Frightened, Billy looked on either side of him to see if his classmates had been messing with him while he was asleep. (He would never call them friends because his only one ever was still Dr. Horrible, but he hadn't wanted to be around lately.) The others' hand-writing didn't match the one on his board, and the blonde began to really panic.

Shakily, he wrote out, "I'm ok. Are you a ghost?"

He felt the darkness returning, and he considered trying to fight it. It was so scary back there all alone...

Billy guessed the mysterious person must have known he was really afraid, because they were a lot quicker this time. He looking down at the board again and found, "Ha! Im not a ghost Im Dr Horrible."

The blue eyed boy began to tremble. He felt like he wasn't in that classroom anymore. No, he was playing with Dr. Horrible in the backyard, reading encyclopedias to him, waiting for him as he sat there, cold and hungry, surrounded by red-

"Miss Finnigan, Miss Finnigan!" A girl on Billy right shouted, waving her hand in the air. "Billy's crying again!" The boy quickly erased his white board, and the whole class turn to look at him. He felt his cheeks burning with shame and embarrassment. The bullies would be at him again for being a baby.

At least... Dr. Horrible would be there?

-{[(•)]}-

From then on, Dr. Horrible tried to not be so forward. He knew it scared Billy sometimes when he would just take over. (There a few times it wasn't so scary, like when Dr. Horrible protected him from the bullies.) So Dr. Horrible tried to be more gentle with the boy.

When Billy was feeling sad, he would sometimes get a strange feeling of comfort from a foreign place inside himself. When he was happy, there was an unfamiliar feeling of happiness besides his.

Sometimes, that little place inside himself would grow hot with anger, upset at the unfairness of the world. Billy would timidly return the comfort he had been given, and usually he would feel a sense of gratitude from the alternate person.

One day, Billy was in his shared room at the orphanage. It was finally empty for once, but he still laid on the ground under his bed for what he was about to do. He had a flashlight in one hand, a pencil in the other, and a piece of paper in front of him. Carefully, he wrote out his alter's name.

"Dr. Horrible?"

The darkness started to come back, and Billy shivered as he went under. Soon, he was back, and he quickly looked down to see what had been written. The words were just as messily written as before, but with an obvious slant to the right. Dr. Horrible was... left handed?

"Hello Billy How are you"

Billy pointedly put in the appropriate punctuation before he gave a response.

"Fine. And you?"

"I'm ok. What did you want to talk about" Billy almost came back, but Dr. Horrible rushed to put the question mark he'd forgotten.

"I- [scribbles] Aren't you lone- [crossed out] bored back there all the time?"

"Sometimes"

Billy stared down at the paper and felt kind of guilty. Dr. Horrible was a person too, and even evil people in prison were allowed to go outside sometimes.

"Would you [scribbles] Would it [more scribbles] How would you like to come out more?"

"That would be nice. Could I?"

Billy fidgeted anxiously. It was nice to let Dr. Horrible spend time outside too, but it was scary back there and he wasn't sure he wanted to be all alone for however long Dr. Horrible wanted to be out.

"Maybe- [crossed out] Could we just start like this?" Billy offered nervously. He still wasn't entirely used to the idea of another person living in his body, but the least he could do was being courteous.

"Sure. How often?"

Billy hadn't thought of that. When would be safe to let Dr. Horrible come out? He had school for most of the day on weekdays, and the orphanage always wanted to do something on the weekends. The other boys in his room were always here except for-

"Wednesdays and Saturdays after school?"

"Okay. I can do your homework on those days."

"I like doing homework!"

"I've never gotten to before."

"Oh. I guess that's true. Okay."

"We should talk about what we like."

"Why?"

"What if we don't like the same stuff?"

"I guess... My favorite color is white."

"White isn't a color! Red's pretty nice..."

Billy shuddered, staring at the world red. His mind was flooded with what little he could remember of that night and he almost started to cry again.

Please don't cry.

The blonde blinked away his tears at the strangely familiar voice. He looked around for who had spoken, but he was still the only one left in the room. Was that... Dr. Horrible?

"Did you just speak to me?" Billy wrote, unsure how to communicate beyond that.

"I think so. I don't like it when you cry."

"I'm sorry. I don't mean to."

"It's okay. I'll take care of you so you don't have to cry anymore."

Warmth flooded Billy, and he blinked at the friendly emotions he was enveloped with. Was this how Dr. Horrible felt about him? Shyly, Billy tried to return the mental hug. Amusement trickled from Dr. Horrible's end, and Billy blushed his embarrassment.

"So... [scribbles] [crossed out] [blacked out with sharpie] What do you want to do when you grow up?" Billy asked, trying to bond with his friend some more. They had been talking about this in class. Everyone else said they wanted to be firemen or singers or something. Billy had nervously admitted he wanted to be a chemist.

"I'm going to rule the world."

"What! Isn't that bad? Only bad guys try to take over the world in books."

"That's what people want you to think. Bad guys are only evil cause they kill people. The good guys are the ones that already rule the world. They just don't want anyone to kick them out."

"Oh. I never thought about that."

Both boys were silent for a long moment. Rowdy screaming came from downstairs. Billy's eyes widened in panic.

"ohno the boys are back what do we do"

"you have to get rid of this"

"how?!"

"the kitchen has an old oven burn it"

Billy quickly crumpled up the paper and slipped into the hallway before he could be seen by his roommates. His small body allowed him to blend into the shadows as he hurried to the kitchen. With a well aimed toss, all evidence of his alter was gone.

-{[(•)]}-

It wasn't until high school that Dr. Horrible started being more demanding.

You don't like those classes anyway! I'll learn all the information, and you won't have to do the homework! It's a win-win!

I said no, Doc, Billy nervously thought back. Our personalities are completely different. People would get suspicious!

But I want to learn things too! How am I going to take over the world if I don't even know the names of the countries I'm fighting?

I... I'll teach you at home, okay? But I can't act weird at school or... Billy clutched his books tighter against his chest and lightly rested his forehead against the cool locker. Despite all the years that had passed, the bullying had never stopped. In fact, it seemed to get worse as everyone went through puberty. Everyone else was buff and chock-full of testosterone, but he was still skinny as a pencil and only had his alter to stick up for him.

You're right. I'm sorry.

This had been an ongoing argument for months because Billy wasn't really used to refusing Dr. Horrible anything he wanted. They had been living peacefully together most of their lives, developing their own personalities and styles. Nothing problematic like this had ever arisen, as unlikely as it may seem.

Doc?

Yes, Billy?

Do you have to take over the world? I don't... It makes me a little scared.

Of course I do! Besides, I'm doing it to help people. You don't want to hurt anybody, and neither do I.

O-Okay.

-[]-

Billy, this class is horrible, and not in a good way. We already know all this stuff!

Billy focused as best he could on the board, trying to ignore the little voice whispering between his ears. Sure, they had already learned all this stuff from their personal study at home, but they had to get good grades in high school or else they wouldn't get into college and get the qualifications to accomplish their dreams.

Seriously, we should just skip this class. I want to work on my invention designs! I know the shrinking ray will be the one, and I can start my career as a villain!

Isn't it early for that? We're still in high school.

I have to start early! Otherwise the Evil League of Evil will never look at us twice!

I guess... But we can't just skip class! You can work on it during lunch.

Fine.

-{[(•)]}-

Dr. Horrible's career was an astonishing success right off the bat. Just before graduation, he had been mentioned in the newspaper, officially recognized as a villain. A hero had risen up just to counter him, and Billy couldn't have been more proud of his best friend.

Unfortunately, some where along the line, Billy realized the sad truth of the matter. There was no way they could both carry jobs during the day. A job as a chemist required constant attention on your experiments, something Billy wouldn't be able to afford if Dr. Horrible was running around playing villain.

Dr. Horrible had been very gentle with him after his realization. Billy never really told him what he discovered, and his alter was still confused why Billy acted depressed and moody sometimes. Still, the mad scientist offered feelings of comfort and made sure they ate and slept properly.

The villain was even more surprised when Billy decided not to go to college like they had been planning. Again, Billy offered no explanation. Instead he told Dr. Horrible that he should have more time to work on his inventions and plans.

Billy resigned himself to being the stay-at-home personality. He did the cleaning, cooking, and any other chores around their apartment. Even after they practically adopted Moist as their henchman, Billy did most of the domestic work. It was calming in a way, even if it wasn't exactly what he had planned for his life.

He needed a bit of calm, as after fights he often woke up in the hospital with his alter suspiciously quiet.

Dr. Horrible started a blog to increase his reputation, and Billy watched them afterwards to support the scientist. It was odd sometimes, seeing his own face saying and doing things he couldn't remember, but it was just another truth he had learned to accept.

-{[(•)]}-

It was laundry day again. Dr. Horrible wanted to work on his blog some more, but Billy had to insist.

We don't have anything to wear, and the laundry basket smells like something died! I'll only be out for a few hours and you can go back to your viewers, okay?

Billy grabbed a basket of clothes and began the walk to the laundromat. It was nice to spend some time outside. He and Dr. Horrible had agreed on a system to spend equal time out, but neither actually ventured beyond the door of their apartment unless they needed groceries or Dr. Horrible had a new plan. It had been a while since their body had some sunshine, and Billy wondered if Dr. Horrible would be okay with taking a break to go somewhere sunny.

Billy stepped into the laundromat and went to his usual machine. As he was loading clothes into it, a pretty young woman entered the laundromat. He looked up in surprise and blushed as she threw some underthings into her own machine. He quickly went back to his own laundry.

Why are you all embarrassed?

There's a really pretty girl...

Yeah? Can I see?

I-I guess...

Billy was dropped into darkness and brought back suddenly. There was a distinct impressed feeling from Dr. Horrible, and the blonde blushed again.

Wow, she is pretty. Go talk to her!

What?! No! I can't do that!

What do you mean- How can you not talk to her?

You know how I am! I'll get all nervous and mess up!

Just go say hello!

Billy shook his head and quickly finished loading the clothes. He put his hands on the top of the rumbling machine, head hanging. Since Dr. Horrible spent the most time interacting with other people, he had the better social skills, even for a villain. Billy just clammed up and struggled to say a thing.

Do you want me to talk to her?

Can I... Can I just do the laundry please? We can- You can talk to her some other day.

Okay, whatever you want, Billy.

-{[(•)]}-

Their lives continued as usual for months. Dr. Horrible's nemesis, Captain Hammer, always got in the villain's way, and Billy struggled to make real, audible connection with the pretty woman at the laundromat. Billy's crush was consistently encouraged by Dr. Horrible, even mentioned in his blog, and Billy offered as much support as he could during the fights with the "corporate tool".

The first time they really talked to the beautiful redhead was during Dr. Horrible's Wonderflonium heist. The scientist had been so surprised Billy had been tossed back into awareness.

"What are you doing?" The woman (Penny?) asked.

I don't know! What am I doing?!

"Texting. It's very important, otherwise I would stop." Billy answered anxiously, glancing at what Dr. Horrible had last been looking at. He tried desperately to finish what the villain had been doing, but he was really out of his depth.

Still halfway between personalities, Dr. Horrible added his opinions to the conversation and typed away on the phone while Billy tried to appear normal to his crush and support her work for the homeless. Honestly, it was a jumbled mess of control, and as soon as Penny was gone, Dr. Horrible quickly took over again.

She talked to me! Billy cheered deep within their mind.

That's great, really, I proud of you, but I need to focus on the heist!

Right. I'm sorry.

It's fine.

The heist almost went off without a hitch, and it would have too if it hadn't been for the arrival of Captain Hammer. Dr. Horrible frantically tried to stop the courier van, while Billy panicked about the endangered civilians.

Billy screamed when they saw the van barreling towards Penny.

Captain Hammer forcefully pushed the blue eyed woman out of the way, surely giving her bruises, and stood in front of the van with his hands extended as if to stop it. Dr. Horrible's phone remote kicked in at exactly the wrong moment and brought the vehicle to a halt.

"You idiot! You could have killed her!" The blonde cried, storming from their hiding place.

A short struggle later, and Billy's heart was crushed while Dr. Horrible made off with the Wonderflonium.

-{[(•)]}-

Where Billy's heart had been broken by Penny's immediate interest in Captain Hammer, Dr. Horrible had been furious with the man's stupidity. Captain Hammer was a danger to those around him, and unless someone took him down once and for all, someone was going to get hurt. And that just wasn't how they did things.

A crazy random happenstance and an incident with the newly finished Freeze Ray later, Billy was nursing their wounds while Dr. Horrible apologized profusely. Eventually, the scientist quieted, and Billy knew he was plotting.

You've got to bond with Penny.

What do you mean?

I don't know. Talk with her, be friendly. Bring her more frozen yogurt.

I'm not sure she'll be interested. Did you see how quickly she reacted to Captain Hammer?

Hero-worship. Don't worry, Billy. I'll come up with a plan to solve both our problems. You can have the girl of your dreams and I can fix what's wrong with the world.

If you say so, Doc...

-{[(•)]}-

Later at the laundromat, Billy was enjoying another frozen yogurt and talking with Penny. He tried to explain their situation to her without actually saying what the problem was, but he acted like himself again and messed up what he was trying to convey. Luckily, Penny was intelligent and kind, and she offered some positive advice.

Then she mentioned Captain Hammer.

Dr. Horrible was yelling at him to get out of there, and he certainly tried. Only to bump right into the man they were trying to avoid. Captain Hammer's arm was like a vice around his shoulders. Billy winced at the bruises forming, his memory flooding with all the times he'd been bullied. He instinctively tried to make himself smaller, and Dr. Horrible was muttering all kinds of reassurances and half-baked escape plans.

Then the hero had to open his big mouth and explain his surprisingly cruel plan. Billy was shocked speechless. Captain Hammer was using Penny- he was going to hurt her! It opened some kind of long forgotten wound in Billy, tearing him apart from the inside. This was all their fault, Penny was going to be really damaged by this and how could they stop a big guy like him- Billy felt himself fading away.

D-Dr. Horrible?

Where Billy felt terror and shame, Dr. Horrible was burning with rage. [It was one thing to hurt Penny, but it was entirely different to go after Billy, and Dr. Horrible would tear apart anyone who so much as tried-]

Don't worry, Billy. I'll take care of him.

-{[(*)]}-

For the next few weeks, Billy was hardly let out. Dr. Horrible was working on something big, and apparently he couldn't even let Billy clean up around the apartment or cook a real dinner. The shier personality was trapped the entire time, and he was confused why Dr. Horrible wouldn't let him out. It wasn't so bad. In fact, it kept him from worrying too much about Penny. He still wished Dr. Horrible would stop forcefully taking over every time he tried to turn on the tv or go out the front door.

The villain didn't spend as much time on his blog during those weeks, and Billy kept receiving an odd mixture of smugness and another emotion he couldn't place from his alter. The other emotion made Billy feel weak, and he tried to send Dr. Horrible his discomfort every time it happened. Things were odd between them; the scientist seemed to be ignoring him.

Finally, Dr. Horrible gave Billy a day to take care of things and re-center himself. It was nice to busy himself with cleaning and tidying up. Past experiences kept him from straying too close to the door or the television, but other than that it was fine.

Until he came to the Death Ray.

What's wrong? You're getting upset.

Yeah... Yeah, I kind of am upset! You-You can't just- A Death Ray?! I thought we weren't going to hurt anybody!

It's just for Captain Hammer.

Just?! There's never any 'just' when it comes to killing! Captain Hammer's a terrible person and he needs to be taken out of power, but not like this! Never like this...

Calm down. It's not a big deal- Hey, don't- Are you crying? Please, don't cry- Please, I can't stand it when you cry...

T-Then take it apart! Destroy it! You can't just... just kill people!

Billy hiccuped and sat down on the nearest available chair. Faint memories trickled in of a night filled with red and flashing lights. Killing would always be wrong, no mater who was being killed or why.

I'm afraid I can't do that, Billy. This is for your own good.

Darkness crept into his vision.

No! Please don't lock me away again!

-{[(*)]}-

Dr. Horrible waited under the curtain for the perfect moment to strike. His Freeze Ray was powered up and ready to fire at any moment, and the Death Ray was prepared for after that. Captain Hammer was giving his obnoxious speech, and Billy was making quiet sounds every now and then.

Finally, the perfect moment came. Captain Hammer opened his big mouth, and Dr. Horrible hit him dead on. The immobilized hero made no signs of life as he began to address the crowd. Stirring up chaos, he fired shots into the air to get any civilians out of the way. The only person who would be endangered tonight was Captain Hammer. Everyone else would live on in the brilliant new society of his own creation...

He leveled the Death Ray with Captain Hammer's nose and ignored Billy's panicked shouting. All he had to do was pull the trigger. Then Captain Hammer wouldn't be able to hurt them- Billy anymore. Just one little movement of his finger-

An odd whirring sounded behind him and Dr. Horrible began to turn. Suddenly, he was punched to the ground. His surprise knocked Billy back out once again, and the blonde tried to sit up only to find a heavy boot-clad foot on his chest.

"N-no, wait-" he chocked out when he saw the death ray, a long glowing crack racing up its side. Captain Hammer ignored his warning and tried to fire. Billy whimpered and ducked away from the explosion. He slowly sat up to observe the damage and noticed a flash of red in the corner of his eye.

Followed by the Captain's screams of pain, Billy made his way to Penny's side. How was she- There was metal and blood, a lot of blood, and her breathing was awful and he could already see her eyes starting to close and- The rush of terrified and desperate emotions awakened Dr. Horrible again, and Billy felt him pushing the mental barriers to have control once more. The blue eyed man pushed him away. He had to stay here with Penny. She needed help and Dr. Horrible just wanted to finish his evil plans-

"Don't worry. Captain Hammer will save us..."

Billy's heart shattered at the same time Penny's stopped.

His hands hovered uncertainly.

His eyes were wide and moist. No tears fell.

His body began to tremble.

The world faded away.

-{[(*)]}-

Dr. Horrible sat in the most recent Evil League of Evil meeting. Bad Horse was giving a speech on his plans for conquering Germany. Everyone was taking notes.

He blinked, and when he opened his eyes, he found that more than a mere second had passed. In fact, it seemed it had been more than a minute. He looked down at his notes. In neat hand-writing that was most definitely not his own, words were written, "Dr. Horrible? May I please come out soon?"

There could only be one answer.

No.

A/N: This musical got to me so bad. I had to write something for it, and I heard this great theory that Dr. Horrible actually had split-personality disorder. So I looked it up, and it actually made a little sense. So this happened...

QUESTION OF THE UPDATE: If you had an alter, who would they be? What would they act like and how are they different than you? I think my alter would actually be a lot like Dr. Horrible. She'd be intelligent and crafty, and she would be very dominating.