Thor Avengers Classic Muscle Costume. Transform your boy from himself into a muscular god of thunder in no time when you dress him in the Thor Avengers Classic Muscle Costume for Boys. This costume features an easy to put on one-piece jumpsuit with Thor's chest armor and faux chain mail sleeves. There is a detachable red cape that comes with it as well. This Thor costume looks exactly like the Thor that is seen in the blockbuster hit The Avengers.