Colossus (Piotr Nikolaievitch Rasputin) is a fictional superhero appearing in American comic books published by Marvel Comics, commonly in association with the X-Men. Created by writer Len Wein and illustrator Dave Cockrum, he first appeared in Giant-Size X-Men #1 (May 1975). A Russian mutant, the character is a member of the X-Men, and is by far the physically strongest member of the team, being able to transform into a strong metallic form.