Crab Mutant (11, 13) - A crab monster. It can spew some foamy substance from its mouth and detach the legs on its back and throw them. Crab Mutant first appeared when the Gorugomes Fruits were becoming scarce. Crab Mutant was later used by Gorgom to kidnap mothers (including the mother of a boy named Taichi) who had just given birth to help the Crab Mutant's eggs hatch to become their frontline soldiers. Crab Mutant proved to be a powerful opponent for Kamen Rider BLACK in the first battle since his hide was hard, but he did get a sample of this monster's blood and discovered that it contained Karado Amoebas which thrive in polluted oceans. He trained himself to find a technique to take on the Crab Mutant when rescuing a dog falling off a cliff caused him to develop a powerful version of the Rider Punch. He searched the local polluted rivers until he hears Taichi's voice when he is caught by Crab Mutant. When the this monster hit an oil barrel, Kamen Rider BLACK got it trapped in a fire. With a powerful version of the Rider Punch and even a powerful version of the Rider Kick, Crab Mutant was killed, the mothers were rescued, and the eggs were burned.