|This article is about a/an kaijin in Kamen Rider Black.|
Flea Mutant was used by Professor Hideomi Kuromatsu to inject his subjects with some chemical followed up with a steroid Kuromatsu used. Hayami was his first subject for him to be a fast racer, but it ended up turning him into a werewolf-like monster later on. Gorgom used the "Coward Hormone" to have Flea Mutant inject it into Kohtaro. Once Kamen Rider Black killed Flea Mutant with his Rider Kick, Hayami returned to normal.
It has great jumping abilities and infect people with the Coward Hormone.
Video game appearances
Kamen Rider Black: Taiketsu Shadow Moon
The Flea Mutant is the fourth mutant opponent and first boss fought by Kamen Rider Black in the video game Kamen Rider Black: Taiketsu Shadow Moon.