Avengers Costumes Assemble! These superheroes are undefeatable and their appeal is undeniable. Iron Man, the Hulk, Thor, and Captain America are all here and ready to be worn by your little one on Halloween. Let him be his favorite crime-fighter if only for one day of the year. He can be inventive like Tony Stark or a patriotic war hero like Steve Rogers. With matching accessories and your child's powerful personality, this costume will be a smash hit. He and a group of his fellow warriors for justice can truly assemble for a super cute group costume idea.