A/N: Woah! I can't believe I'm updatig something. Maybe this is not so "shippingful", but is the best idea I had for the prompt so far.
Hm...well, enhoy the story! :D
This is going to be short.
"Mathias! Hurry up and get out of the bathroom! It's already late!" Lars called out, knocking several times on the door.
"Can't I just put a cape on pretending I'm Superman? This costume is too fucking embarrassing!" whined Mathias, ignoring the request from the outside.
Lars sighed: Kiku invited them both to a party at his place. It was a cosplay event, and he specified that everybody should have worn a costume. Nothing too strange, if it wasn't for Alfred's "great" idea to pick out a costume randomly. Of course, luck wasn't by Mathias side at the moment of choosing.
"Come on, it's just for tonight! Think about Laura that has to wear a golden helmet with cat ears all night long!" Lars hoped this would get his boyfriend out of the bathroom, he was running out of ideas involving good manners.
"Celty is a great character, and doesn't matter what you make her wear, she will look nice anyway!"
Of course, Mathias didn't want to collaborate.
"Okay, Mathias, if you don't get out in two seconds, I'm going to bash the door in! Since is your house!"
There was no answer for a while. Lars sighed "Please, make an effort. Don't think that I particularly enjoy going around with this two huge plastic stuff pending from my sides, laced like a roast-beef from feet to head?" Again Mathias refused to answer "I'm lending you the swords to play the piñata game on Alfred"
Lars wasn't finished to speak, that Mathias opened the door wide, a determined look on his face, as he put the pink fluffy hears on his head, the last detail to add to a stuffed a pink costume "Get out of my way, Cleafairy-man is going to beat the shit out of some Amrican ass tonight!"
Useless to say, that night turned into a nightmare for the poor Alfred. All the guests, strangely, agreed to play the piñata game with him as a reward for his brilliant ideas.
A/N:Btw, Lars' costume is someone from SnK, I haven't figured out who myself. Maybe Erwin could be the more suitable.