Squeak fulfills what he is programmed to do, which in this case is to annoy enemies by talking constantly. Although not malignant, he is energetic and talkative for hours on end without stopping, tiring out, or even showing signs of needing to breathe. Despite being programmed for nonstop talking, Squeak seems to have some level of self-control as shown when he annoyed the original Leroy by talking incessantly, after which Leroy threateningly shot a blast at him, causing Squeak to immediately become quiet.
Squeak can speak fluent English and go on talking nonstop for a considerably long amount of time. He can talk extremely fast in a high-pitched, squeaky voice, hence his name.
Experiment 110 was the 110th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to irritate people and entire populations by talking nonstop constantly. 110 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.
At an unknown point after this, Experiment 110 was activated and captured by Jumba.
In "Spike", Jumba tested a reprogramming device on 110 (later named Squeak) to make him less talkative without success, as the device just exploded. Even Pleakley was driven insane by Squeak's incessant blabbering, and begged him to stop talking.
The first 624 experiments, including Squeak, were rounded 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.
Squeak participated in the following battle between the experiments and the Leroy clones, but was briefly threatened by the original Leroy's plasma gun when Squeak wouldn't stop talking. He also made a referee whistle sound when Kixx punched a Leroy clone over one of the stadium's goalposts.
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 ʻOe", which caused the Leroy army to shut down due to the original Leroy's fail-safe.
Squeak made an appearance in the Stitch! anime along with Frenchfry, Pix, Tickle-Tummy, and Houdini after Hämsterviel kicked them out for being considered useless. He made a later appearance with Shrink, Clip, Nosox, and Retro. He made a third appearance in aiding Stitch in battle against Dark End. He also appeared in the special Stitch and the Planet of Sand.
- According to what he says in his first appearance, Squeak's astrological sign is Leo.
- Squeak talks in a high-pitched, squeaky voice, hence his name.
- He is also one of the very few known experiments that can speak English fluently.
- Squeak is one of the few experiments to not appear in the group photo at the end of Leroy & Stitch.
- Squeak's pod color is red in the Stitch! anime.
- Squeak appeared in two anime episodes. In the English dub, he is called "Squeak" and "Squeaky" in different episodes.
- In "Hämsterviel's Epic Secret" he was referred to as "Squeaky" throughout the episode.
- In "Experiment-A-Palooza", he is referred to as both names by Yuna. Squeak also mentions Lilo and that she had given him his name, but he prefers to be called "Experiment One-One-Oh".