Stoneface, A.K.A. Experiment 525, is an illegal genetic experiment created by Jumba Jookiba. He is designed to eat through solid rock (does so by using his strong jaws and sharp teeth). His one true place is working in a mine.
Experiment 525 was the 525th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to eat through solid rock.
525 and the other first 624 experiments were deactivated and smuggled to Earth by Jumba during his mission to capture Experiment 626.
All of the experiment pods were released and scattered across the island of Kauai.
At an unknown point, Stoneface was activated, tamed, and named Stoneface.
All 624 experiments, presumably including Stoneface, were round up by Leroy and taken to a stadium to be destroyed. However, Lilo, Stitch, Jumba, Pleakley, Reuben and Gantu arrived before the experiments could be destroyed.
It is unknown whether or not Stoneface participated in the following battle between the experiments and the Leroy clones.
The Leroys soon gained the upper hand in the battle, but were defeated when Lilo, Stitch, Reuben and several other experiments performed the song Aloha Oe, which caused the Leroy army to shut down due to the original Leroy's failsafe.
Cannot process metalloid substance, and creates massive caverns that implode on itself.