Yin, A.K.A. Experiment 501, is an illegal genetic experiment created by Jumba Jookiba. She is designed to attack with blasts of water from her tentacles. Her one true place is creating a new island with Yang. She is voiced by Frank Welker.
She was activated with Yang when her pod fell into a pool. Jumba said that should the two touch each other, they will cause a giant explosion, but they turned out to be a good example of Yin and Yang; they use fire and water to create a new island. She is seen in the episode "Finder" playing poker with Stitch, Yang, Richter, and Cannonball and at Lilo's slumber party in the episode "Dupe" with Yang, Richter and Cannonball. She was also one of the experiments reverted to evil in "Angel" and one of the players on Lilo's softball team in "Slugger". She filled the pool for "Jumba & Pleakley's Bed & Not Breakfast", and was part of the "rebellion" in "Checkers".
An experiment of few words, Yin was shown to be cocky, short-tempered and reckless before her rehabilitation. She is single-minded and will focus only on what's right in front of her, paying little heed to anything else going on around her. This clearly demonstrates an overconfidence in her own powers, as Yin considers them more than adequate to handle any threat. She is shown to not really care about other people's surroundings when using her squirting powers. However, she would defend her friends and ʻohana loyally, alongside Yang.
Yin is a blue octopus/squid/waterhose-like experiment with eight waterhose-like tentacles, a slug-like body, black eyes and three tendrils on her head.
Yin can absorb water into her head through her tentacles, and then release the stored water in powerful sprays when she wishes. Her tentacles can also be used for filling pools, bathtubs and birdbaths. It is also shown that when Yin and Yang combine their powers, they are able to create rock/land.
If Yin does not have any stored water or access to a water source, she will be rendered harmless.
- Although Yin is actually a female, Lilo erroneously referred to Yin as a male.
- Her name is derived from the concept of Yin and Yang; in this case her name stems from the force of Yin, which represents femininity, water and cold, fitting her nature.
- Though Yin apparently has no mouth, a mouth is seen on her in "Angel" when she and other experiments carry Stitch out of a ship. A mouth is also seen on Yin in a few shots of "Slugger", especially during Lilo and Mertle's argument over the game rematch.
- Yin's pod color is blue.
- Her pod number was also given to Richter (in "Ace"), most likely due to Jumba's untidy database.
- Yin is described by the experiment computer screen as, "Experiment 501. Primary function: Water sprayer".
- Yin's head and body appear in the online game Jumba's Lab.