Troller

Trollers were huge, horned, worm-like beasts that lived beneath the Po-Metru sands. Its mouth was large enough to swallow an entire block of a Metru. Toa Metru; Onewa, Nuju, Whenua and Turaga Lhikan encountered one in when they broke out of there cell in BIONICLE Adventures 4: Legends of Metru Nui.