I really really really want to start collecting weird x-men children's books, because the ones I have seen are absolutely batshit.
(FUN FACT! THERE IS AN EARLY READERS ADAPTATION OF DAYS OF FUTURE PAST. THE COMIC.)
One of my oldest's favorite books is an early reader book about Loki causing mischief in an elementary school.
"Loki took the cookies! Loki made the Hulk blue! Loki was feeling left out!"