Slug Moth Mutant (11, 27) - A slug moth monster. It can shoot spikes from its body and its cocoons it has displayed can violently explode upon detections of heat and/or friction energy. Slug Moth Mutant first appeared when the Gorugomes Fruits were becoming scarce. Slug Moth Mutant was later used by Gorgom to render the city's energies helpless (including transformation energies). Kotaro could not transform into Kamen Rider BLACK in the first battle due to the cocoons until a powerline fell on them. Kotaro transformed into Kamen Rider BLACK and Slug Moth Mutant later retreated. Slug Moth Mutant later attacked a power plant with his cocoons which interferes with the heart surgery of a boy named Hisao. In the second encounter with Slug Moth Mutant alongside the High Priests, the bridge that Kotaro was on broke upon responding to Baraom's attack causing Kotaro to fall. Kotaro evaded them and made his way to the power plant in which even if he took out the power source, there would be no power at the hospital. Slug Moth Mutant and the High Priests had Kotaro at their mercy and Slug Moth Mutant was trying to rip out the Kingstone in Kotaro. Kotaro poked Slug Moth Mutant's eyes before jumping into the air to transform into Kamen Rider BLACK. Kamen Rider BLACK ripped off all of Slug Mutant's spikes. Once Slug Moth Mutant was killed by the Rider Kick, power was restored to the city.