Everyone knows that Stiles loves batman. If you walk into his room you'll see a least one batman comic on his desk, a couple of action figures on his bookshelf and a batman sticker on his laptop. If you walked over to his closet and opened it you'd find an old batman costume. So yeah, the point is that Stiles loves batman.
But Derek? Derek has a thing for superman. He'll never actually say it out loud and admit it but Stiles knows for a fact that the werewolf owns all of the superman movies. Every. Single. One.
So maybe one day Stiles bribes Cora with food to find out if Derek does in fact like Superman. And maybe he finds out all about how little Derek used to ask his dad to lift him up so that he could fly like superman, or maybe how the werewolf would dress up as superman for Halloween and any other day he could find where his parents would hide the costume. He might have also found out about how Derek would always say that he would one day find his own Wonder Woman to marry.
And maybe, just maybe Stiles just happened to see a Wonder Woman costume online before Halloween. And he might have also kinda put it on one night when he totally didn't know that Derek was supposed to go pick up some books about whatever supernatural creature was in town.
And if Derek just happens to freeze up before attacking him(with his mouth) nobody has to know..
(A/N)
~I know this is really really short but I've been working on writing some stoyd(stilesxboyd) fics lately so I took a couple of minutes to write this but I'll try to write more sterek this weekend for you guys :)