Experiment 111 was the 111th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to tear up the ground beneath him. 111 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. Against statistically unlikely (but not impossible) odds, several experiment pods landed in one location: Mrs. Hasagawa's yard, 111's pod being one of them.
At an unknown point, Mrs. Hasagawa mistook 111's pod for an apricot and placed it in a colander for later consumption along with numerous other pods.
After Lilo and Stitch redecorated Mrs. Hasagawa's yard without her permission, she was less than thrilled with the results, but decided to thank them for their work with the "apricots." The pods were then revealed, but before Lilo and Stitch could stop her, she washed them with a watering can, thus activating the experiments.
After his activation, 111 began to carry out his primary function by tearing up the lawn in Mrs. Hasagawa's yard. Lilo and Stitch believed the experiments to be a danger to Mrs. Hasagawa and, along with Jumba and Pleakley, decided to capture them all. When Stitch was trying to convince Experiment 288 to go into a container, 111 started approaching. Stitch then threw 288 into the air and used the container to capture 111 instead.
111 and the other experiments were about to be taken away, but were returned to Mrs. Hasagawa when Lilo and Stitch saw how much she cared for them. 111 was then named Mulch.
In "Woops", Mulch was oddly seen as one of the captive experiments in Hämsterviel's prison cell, although he is barely seen, suggesting Gantu caught Mulch, but this was an error. Mulch was then sent back to Gantu after Experiment 600 caused mischief and nearly blew Hämsterviel's cover to the prison guards.
The first 624 experiments, including Mulch, were rounded up by Leroy and taken to a a stadium to be destroyed. However, Lilo, Stitch, Jumba, Pleakley, Reuben, and Gantu arrived before the experiments could be destroyed.
Mulch participated in the following battle between the experiments and the Leroy clones.
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 ʻOe", which caused the Leroy army to shut down due to the original Leroy's fail-safe.
- Mulch doesn't always seem to look where he is going, as Stitch was able capture him by placing a containment orb in his path. Similarly, he was easily captured by a Leroy clone by walking onto a net trap in plain sight.
- Mulch's pod color is blue.
- In "Woops", Mulch erroneously appeared with Gantu's other captive experiments, although he is barely seen, but he was already living with Mrs. Hasagawa, and Lilo and Stitch discovered him while Gantu was asleep.
- Mulch and Splat are the only known experiments to have a set of rollers as limbs. In Mulch's case, they are his hind limbs.
- Mulch is one of the few experiments to not appear in the group photo at the end of Leroy & Stitch.