Herbert Landon in his mutant monster form.
Herbert Landon was the main antagonist of The Mutant Agenda - a crossover between the 90s Spiderman cartoon and the X-Men, he was a brilliant but completely immoral scientist who specialized in mutant DNA and was at some point a friend of Beast prior to his transformation into a mutant.
Unlike Beast Landon would continue to harbor a deep hatred of mutants his whole life, to the point he created a chemical substance specifically for the purpose of killing all mutants that he openly stated he would wipe out all mutants using his invention, which Beast rightfully warned was basically genocide.
However in a twist of fate Landon would become a victim of his own madness when the Hobgoblin caused him to fall into his chemical bath, instead of being destroyed on a molecular level he would emerge as a horrendous, mutated, monster.
Appearance[]
Landon is a four-armed reptilian mutant with a whip-like tail.