Geigenstein, A.K.A. Experiment 201, is an illegal genetic experiment created by Jumba Jookiba. He is designed to eat books so no knowledge is gained.
Experiment 201 was the 201st genetic experiment created by Jumba with Hämsterviel's funding. He was designed to eat books so no knowledge is gained.
201 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 the unknown point, he was activated, captured, tamed and named Geigenstein.
This experiment was one of the pods in Mrs. Hasagawa's dish that was not activated.
The first 624 experiments, including Geigenstein, were rounded 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 Geigenstein 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 fail-safe.
Geigenstein is a tall Nosy-like experiment with long, floppy ears and a smaller nose.
- Geigenstein's pod color is white.