|This article is about a/an kaijin in Kamen Rider, the original series.|
Arikimedes (アリキメデス Arikimedesu, 35 & Rider vs Shocker) - A queen ant monster. She was able to release a red acid that could easily melt humans and metal and used used traps during battle. Her personal emblem, worn by the soldiers under her command, was an ant. Hayato Ichimonji and Kazuya Taki attacked the outpost commanded by Arikimedes and stole an egg from there. Trying to recover it, they fought again. She was destroyed after getting hit by Kamen Rider #2's Rider Kick and falling into a pond of formic acid.
Arikimedes made a brief return appearance in the monster army of the Kamen Rider vs. Shocker movie, but did not actually have an active participation there.
- Arikimedes' name is likely a pun on Greek mathematician and inventor Archimedes.