The origin of the Man - Thing is a classic case of scientific hubris gone wrong. Ted Sallis was involved in some top - secret experiment related to a serum. He was in the Everglades when trouble came his way. Instead of surrendering, he took the serum which was not fully developed. This act changed him forever. As the Man - Thing, he has no real human consciousness left. He exists more as a force of nature in the swamp. His form is a grotesque but also a powerful one, and his story serves as a cautionary tale about the dangers of unchecked scientific exploration.
Captain Marvel is not male in the comics. The comic version features a female character who goes through various adventures and battles with her distinct abilities.