Mr. Stenchy, A.K.A. Experiment 254, is an illegal genetic experiment created by Jumba Jookiba. He is designed to use his charm to get the enemy to take him back to their headquarters, where, 48 hours after his activation, he emits a vile odor that makes the location inhospitable. His one true place is on Plorgonar (Pleakley's home planet), where, unlike Earth, his stench is considered a rare and valuable perfume. He is voiced by Frank Welker.
Due to his disarming cuteness, Mr. Stenchy gains very much attention from humans and even certain alien species, but not so much from other experiments. He also appears to act as cute as he looks, being very loving and friendly towards anyone who gives him affection.
Mr. Stenchy is a small, irresistibly cute light pink experiment with a big head with big blue eyes, two puffy antennae, a small tuft of hair and a small body.
Mr. Stenchy appears disarmingly cute to everyone except other experiments, but then emits an extremely noxious, foul odor 48 hours after he is activated, which makes 40 square miles of an area uninhabitable for decades.
Apart from his disarming cuteness and noxious stink, Mr. Stenchy is mostly defenseless. Also, other experiments are totally immune to Mr. Stenchy's charm.
Mr. Stenchy appeared twice in the Stitch! anime. He was first seen when he fell in love with Stank, and again later on when Hämsterviel made numerous clones of him and Mrs. Sickly as Christmas toys. It is revealed that when his stench is combined with Mrs. Sickly's, it could cause an explosion that has the power to destroy a planet.
- Mr. Stenchy is one of the rare experiments to have sclerae and pupils instead of solid black eyes, the others being Mrs. Sickly, Skip, Clink and Nosox.
- Stitch and Reuben were unmoved by Mr. Stenchy's cuteness, as Jumba pointed out that other experiments are immune to Mr. Stenchy's charm.
- Pleakley is revealed to be the only one able to tolerate Mr. Stenchy's stink, unlike everyone else.
- Mr. Stenchy's pod color is green.
- Mr. Stenchy is described by the experiment computer screen as, "Experiment 254. Primary function: Stink bomb. Emits a noxious odor that makes the location inhospitable".
- In Leroy & Stitch, Mr. Stenchy inexplicably returned to Earth from Plorgonar. Also, he did not produce his stink, suggesting it wears off after a while or he has learned how to control it.
- Mr. Stenchy is one of the few experiments to not appear in the group photo at the end of Leroy & Stitch.
- In the Stitch! anime, Mr. Stenchy has a wife named Mrs. Sickly.
- Mr. Stenchy's head, antennae and ears appear in the online game Jumba's Lab.