"Mizu" meaning water, and "geiko", which is Kyoto slang for "geisha"
To attack the Sailor Senshi
Chiharu Kataishi (original anime)
Tiger's Eye was looking into Rei Hino's dreams when Sailor Moon and Sailor Chibi Moon appeared, so he summoned Mizugeiko to fight them. Her attack was stopped by Sailor Mercury using Shine Aqua Illusion. Sailor Chibi Moon summoned Pegasus with Twinkle Yell, and Sailor Moon destroyed Mizugeiko with Moon Gorgeous Meditation.
She attacks by shooting beams of deadly water, or else rainbow beams that shoot out deadly teru teru bozu charms.