Mutants

Mutants are entities created through genetic modification. The majority of mutants are classed as Mysterious Beings.

Overview
Mutants are man-made creatures, which are created by modifying genes with science. They appear in various shapes and each one is unique, possessing abilities of various different species or uniquely designed attributes given by their creators.

Dr. Genus in particular excels in the research and creation of mutants, having created dozens of them by affecting human genes in his House of Evolution.

While Zombieman himself is a Mutant, human society doesn't seem to view him as a Mysterious Being, but rather accepts him as a human being, given his status as a hero.