Siberius was an icy planet which was home to the Frozen Base used by the Unknown Thief, and was the location where the thief tried to destroy the Protopet. The thief was foiled by Ratchet, who retrieved the Protopet and returned it to Abercrombie Fizzwidget. The planet was similar to Hoven and the water on Siberius was also similar to the water on Hoven and Grelbin. Ratchet would freeze if he touched it. Siberius was located in the Bogon Galaxy.