Yin

Yin, A.K.A. Experiment 501, is an illegal genetic experiment created by Jumba Jookiba. She is designed to attack with blasts of water. Her one true place is creating a new island with Yang (502). Yin is voiced by Frank Welker.

Bio
Experiment 501 was the 501st genetic experiment created by Jumba with Hämsterviel's funding. She was designed to attack Jumba's enemies with massive blasts of water.

501 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 501's pod landing in a tree.

Lilo & Stitch: The Series
501's pod fell out of the tree and into a pool below, activating the experiment. 501 then absorbed the pool's water, and, armed, set out to cause chaos.

501 traveled to the beach, where she was discovered by a boy. When the boy squirted 501 with a water guns, the latter responded by attacking him and the rest of the beach with blasts of surging water.

501 later attacked Kokaua Town. Stitch tied her tentacles together to render her defenseless, but this only caused 501's stored water to gush out and cause a flash flood.

501 was chased by Lilo and Pleakley through a jungle, but the two failed to capture the former. While draining a pond to arm herself, Experiments 501 and 502 met for the first time. However, they were ambushed and captured by [Captain Gantu|[Gantu]] before they could make physical contact.

While returning to his ship with the two captured experiments, Gantu fell for a trap laid by Reuben, allowing 501 and 502 to escape.

When Stitch later tracked 501 down to a backyard, the latter used a running tap to gain an infinite supply of water to use as ammo. However, 501's ammo ran out when Lilo turned the tap off, allowing Stitch to easily capture her.

501 and 502 were then rehabilitated, named Yin and Yang, and given a one true place using their combined powers to create a whole new island.

Yin and Yang reappeared in "Elastico".

In "Houdini", Yin was one of the audience for Stitch's magic act.

In "Finder", Yin was seen playing poker with Stitch, Cannonball, Richter and Yang (502).

In "Dupe", Yin was one of the experiments who came to Lilo and Stitch's slumber party. However, she was forced by Pleakley to leave due to her destructive behavior.

In "Angel", Yin was one of the experiments who Angel reverted to evil using her song. Yin and the other rehabilitated experiments attacked Stitch aboard a ship, but Angel turned them back to good before they could finish Stitch off. Working together, the experiments were then able to successfully escape the ship.

Yin reappeared in "Slugger".

In "Shoe", Yin was one of the experiments who helped turn Jumba and Pleakley's ship into a hotel.

Yin was one of the experiments in "Checkers" who joined Stitch in a rebellion against Gantu.

In "Ace", when the CEO of EGO arrived on Earth to decide whether or not Jumba was still evil, Yin and Yang posed as mutant creations as part of a hoax to fool the CEO.

Leroy & Stitch
The first 624 experiments, including Yin and Yang, 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.

Yin and Yang participated in the following battle between the experiments and the Leroy clones by using their combined powers to encase Leroys in rock.

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 Oe, which caused the Leroy army to shut down due to the original Leroy's failsafe.