Millie, A.K.A. Experiment 220, is an illegal genetic experiment created by Jumba Jookiba. She is designed to plug up air holes in filters crucial to all hyperdrives. Her one true place is in the space navy.
Experiment 220 was the 220th genetic experiment created by Jumba with Hämsterviel's funding. She was designed plug the holes in air filters crucial to all H-drives. 220 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 some point, 220 was presumably activated, captured, and named Millie.
The first 624 experiments, including Millie, 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.
Millie participated in the following battle between the experiments and the Leroy clones by grabbing and strangling Leroys.
However, 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 ʻOe", which caused the Leroy army to shut down due to the original Leroy's fail-safe.
Millie is a giant green millipede-like experiment with a koala-like face, a wide mouth, a big blue nose, black eyes, Nosy (199)-like ears and ten short tentacle limbs. Her legs are stubby and dotted with black toes.
Millie can plug holes in air filters by using her long tentacle-like arms.
- Millie's pod color is green.