Slimy

Slimy, A.K.A. Experiment 390, is an illegal genetic experiment created by Jumba Jookiba. He is designed to leave slippery slug trails. He was captured by Captain Gantu, but was rescued in "Snafu". His one true place is making a sci-fi waterslide at parties.

Bio
Experiment 390 was the 390th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to leave slippery slime for enemies to slip on.

390 and the other first 624 experiments were deactivated and smuggled to Earth by Jumba during his mission to capture Experiment 626.

Stitch! The Movie
All of the experiment pods were released and scattered across the island of Kauai, with 390's pod landing in a sleeping tourist's belly button at a hotel.

The man later awoke and flicked 390's pod into the nearby swimming pool, activating the experiment.

Lilo & Stitch: The Series
In "627", 390 was tracked down and captured by Stitch. However, 627 was able to take 390 from Stitch and hand 390 over to Gantu.

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