Poxy

Poxy, A.K.A. Experiment 222, is an illegal genetic experiment created by Jumba Jookiba. He is designed to enter the bodies of and disease popular planetary leaders. He was captured by Gantu, but was rescued in "Snafu." After Leroy & Stitch, Poxy was reprogrammed to fix health problems.

Bio
Experiment 222 was the 222nd genetic experiment created by Jumba with Hämsterviel's funding. He was designed to enter the bodies of popular planetary leaders' bodies, the disgusting symptoms which 222's presence would cause would result in the disgusted public revolting against the infected leader.

222 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, with 222's pod landing in a sugar crop.

Lilo & Stitch: The Series
222's pod was caught up in the machines used to extract sugar from the crop, and thus the pod eventually made its way into Pleakley's cereal, where the milk activated the experiment before it was eaten with the cereal by Pleakley.

Lilo and Stitch shrunk themselves to microscopic size and entered Pleakley's body to find and capture 222. After a long chase through Pleakley's body, Lilo and Stitch were able to capture and extract 222 when the latter became stuck in Pleakley's earwax.

Lilo planted 222, named Poxy, in Gantu.

As Gantu was well in later episodes, it can be presumed that Poxy was extracted and sent to Hämsterviel, then back to Gantu in "Woops."

Poxy reappeared in "Snafu," and was freed along with Gantu's other captive experiments by Lilo, Stitch, and several other experiments in a rescue mission.