This came to me one day. I had to write it. I'm sorry.
Disclaimer: Marvel owns all characters mentioned. I'm merely borrowing them.
It wasn't supposed to go like this, Loki thought bitterly to himself as he reflected on what had occurred only an hour ago.
It had been a normal enough Saturday. Loki was lounging on the roof of his favorite dilapidated warehouse, the one in front of the skyscraper with the shiny, mirrored windows (even crazed super villains enjoying looking at their reflection). He was enjoying the sunny afternoon by rearranging the clouds to spell out various assumptions about Nick Fury's mother as well as bewitching the pigeons to dive-bomb anyone who walked by. It was the perfect way to unwind after spending the morning wreaking havoc in Brooklyn by way of his illusions. He had left a couple of clones over there to spice things up for whichever superhero was unfortunate to be working that day. I hope it's the man of spiders, Loki mused to himself, sending a particularly stout pigeon into the woman who was unfortunately chose the wrong moment to exit her Jetta. Ahh, yes, the perfect Saturday afternoon. What could possibly go wrong?
"Brother! Cease with this mischief!"
Damn. It would seem that this perfect Saturday was about to be ruined by the proverbial thorns in Loki's side. He sighed, rearranged the cloud comparing Mrs. Fury to that of a communal horse (because everyone has had a ride—wasn't he clever?) into something rude about Thor's intelligence.
"Brother! That is not true, I do not think my brain is filled with horse droppings." Loki smirked before bewitching a passing seagull and aiming it straight for Thor's face. He laughed out loud as Thor spit out a mouthful of feathers before tossing one very shell-shocked bird to the ground. Loki would have continued to laugh if he hadn't noticed that Thor was alone.
"Where are your little friends? Planning on ambushing me?" Loki asked as he rose up from the dark green lawn chair he had nicked from a Home Depot two weeks ago.
"They are dealing with your earlier shenanigans. Your illusions had nearly taken down their bridge." Thor answered sternly.
"Oh, well I am just so sorry!" Loki said, throwing his arm over his forehead.
"It is alright, brother, as long as you see the error of your wa—" Thor was cut off by another bird to the face.
"Thor, I am a little hurt that after all this time together, you still cannot pick up on my use of sarcasm." Thor decided to ignore that in favor of slinging the bird right back at Loki. Thor would have been successful if Loki had not deflected the bird with a flick of his wrist. Loki sighed again before picking up his scepter, figuring that beating Thor (or at least mocking him into next week) would pick up his spirits. Loki aimed the magical staff at Thor's cape, causing a small green fire to break out in one corner.
Lucky for Thor, he remember S.H.I.E.L.D.'s fire safety training video and executed the perfect "stop, drop, and roll" squashing the fire and as well as the seagull that had been previously flung into his face.
"Loki, that wasn't funny!" Thor yelled, examining the damage done to his cape.
"On the contrary, it was quite hilarious." Loki smirked. Next time he would aim for the hair. Really, he was just passing the time before Thor's band of ragamuffins showed up, when he would have to crank it up.
"But you ruined my cape!" Thor shouted, picking up Mjölnir.
"Well, you ruin my life!" Loki shot back, aiming his scepter directly at Thor. Forget the hair, Loki was going straight for the face. Maybe I'll replace his nose with a snout…
Loki barely had time to react to Thor throwing Mjölnir, jumping out of the way only to watch as a magical hammer destroyed his new lounge chair. Thor jumped on to the building, picked up his hammer, and faced Loki.
"Will you ever cease with this treachery?" Thor asked, swinging Mjölnir. I'll dent his face. But not too much, for Mother would not like that
"Never." Loki hissed, gearing up his scepter. Snout be damned, I'll turn him into a newt.
What happened next would be talked about for years to come. Loki aimed the scepter at his sbrother/s foe and let loose a powerful blast of blue light, but instead of hitting Thor, it deflected off of Mjölnir and was headed straight back at Loki. Quickly, Loki ducked and the magic missed him, instead hitting the mirrored window of the window behind him and rebounding, aiming itself back at Loki.
"Loki! Look out!" Thor shouted, dropping his hammer and throwing himself at Loki in order to push him out of the way. Unfortunately, Thor's aim was off and instead of getting them both out of the way, it only served to knock them both down into the path of the magic.
There was loud boom and a bright flash of light, so bright and so loud that it was heard as far away as Brooklyn.
"Oh my god, what was that?" Natasha exclaimed, pointing at the blue light in the distance.
"I don't know, but I'm pretty sure we should probably check it out." Tony said.
Back at the warehouse
Everything had finally settled when Loki finally came to. The blast was a bit more powerful than Loki had anticipated, especially since it had been reflected, twice. He tried to sit up, but it found it difficult with Thor draped over him.
Thor! Kindly remove your carcass from being, now! Loki hissed. Thor stirred slightly, still out from the blast. Loki huffed before noticing that looked off about Thor. For one thing, he was smaller. And hairier. And a dog.
A dog! He had transformed Thor into a dog. A big, blonde dog. It's not a newt, but it will suffice, Loki chuckled to himself, trying to remove himself from the sleeping dog. It was difficult, but Loki finally extracted himself from under Thor. Better. Loki tried to stand up, which is when he finally noticed that Thor wasn't the only one who was different.
I feel so strange, he thought to himself, I feel small…and hairy… Loki finally looked down at himself and noticed that his magic had turned him into a cat. More specifically, a kitten.
Loki's anguished yowl was more than enough to wake Thor.
Brother! Are you okay? Thor asked, hopping up from his heap on the ground. Brother? Where are you? He looked around before noticing the pitch-black kitten with the green eyes.
Brother…is that you? Thor asked, incredulously. Thor was no stranger to Loki's predilection for shape shifting, but a kitten was the last thing he'd expect Loki to change into.
Of course it's me, you dolt! Loki hissed miserably. Thor frowned, looking past Loki at his reflection in the window.
Loki…am I now a dog? Or is this one of your illusions?
It's real, Thor. We have been reduced to common house pets.
Thor's anguished howl could be heard all over the city.