|This article is about a/an kaijin in Kamen Rider Black.|
Earwig Mutant was used by Gorgom to manipulate the quartz into causing earthquakes enough to sink Japan. When the recently captured Professor Smith's quartz failed the test, Gorgom began to seek the Ultra Quartz which was supposed to be presented by the late Professor Jones. Earwig Mutant later captured Professor Yanagi and the Ultra Quartz. Kohtaro found the location of the captive scientist and engaged in battle with Earwig Mutant and Professor Yanagi was really Interpol agent Ryusuke Taki in disguise. Taki freed the professors and later helped Kamen Rider Black use the Ultra Quartz to break off Earwig Mutant's right hand. Kamen Rider Black then killed Earwig Mutant with the Rider Kick.
It can shoot energy beams from its blade-like hands and attack with its abdomen.