Bee Mutant is a bee monster who assisted Bishium into placing pendants with bee eggs that hatch to place a deadly illness on anyone wearing them. It can fly, and shoot stingers from its abdomen. Bishium and Bee Mutant took control a girl named Etsuko and used her to be the "Queen." When Bee Mutant took Etsuko and Kaoru hostage, Kotaro became Kamen Rider BLACK and pursued them. As Kotaro was battling Bee Mutant, Bishium created a vacuum beehive to suck in Etsuko and Kaoru. Kamen Rider BLACK used his Rider Punch on Bee Mutant's stinger. Once Kamen Rider BLACK killed Bee Mutant with his Rider Kick, the bee eggs on the pendant disintegrated and Etsuko and Kaoru are saved.