The Subterranean Worm is a race of giant, strong, tentacled creatures that dwell deep in Onu-Wahi and are spoken of mainly in legends, and occasionally spotted by miners. They are blind and navigate by hearing, and are rumored to feed on Protodermis. They have lived underground since before the Matoran came to Mata Nui. The one described in BIONICLE Chronicles 4: Tales of the Masks was huge, tentacled, bleach white and had no eyes. Instead, it navigated by sound, which Onua Nuva used to his advantage by creating a sound that caused it pain because of its enhanced senses.