Faust: Love of the Damned (movie, 2000)

An artist, John Jaspers sells his soul to the mysterious "M" in order to get revenge on the people who killed his girlfriend. Soon, he realizes everything has a price, and he is transformed into a horned demon with a passion for killing. He learns that M plans to release the Homunculus, a giant Lizard-like monster onto the earth, opening the gate to hell. Now, Jaspers must stop M before he can let the apocalypse begin.