Colossus (Piotr “Peter” Nikolayevich Rasputin) is a fictional character appearing in American comic books published by Marvel Comics. Created by writer Len Wein and artist Dave Cockrum, he first appeared in Giant-Size X-Men #1 (May 1975).

A Russian mutant, he is a member of the X-Men. Colossus is able to transform himself into metallic form, making him the physically strongest of the team. Even when his powers are not engaged, he is still a physically imposing figure of 6 ft 7 in (200 cm) in height. He is portrayed as quiet, honest, and virtuous. He has had a fairly consistent presence in X-Men-related comic books since his debut. A talented artist, he only reluctantly agrees to use his powers in combat, feeling it is his responsibility to use his abilities for the betterment of human- and mutant-kind.

Wizard ranked Colossus at 184 on the “Top 200 Comic Book Characters of All Time”. In 2006, IGN placed Colossus in the 10th spot of their list of “The Top 25 X-Men”. In 2013, ComicsAlliance ranked Colossus as #22 on their list of the “50 Male Characters in Comics”.

In film, Donald MacKinnon portrayed a cameo as Colossus in X-Men. Actor Daniel Cudmore took over the role of Colossus in X2 (2003), X-Men: The Last Stand (2006) and X-Men: Days of Future Past (2014), and Stefan Kapičić provides the voice of a CGI character in Deadpool (2016) and Deadpool 2 (2018).