A Viola is a creature that resembles a head that is found in Ridley's Lair. They appear in Metroid, Metroid: Zero Mission and in Super Metroid. Normal ones have the same AI (Artificial Intelligence) as a Zoomer. There are two main types: a orange type and a blue type. The adult version is called a Multiviola.
"These Multiviola larvae creep around the floors and ceilings. The green ones take two shots to beat, while the yellow ones take four."
"They only move around on small, rocky areas."