Upon encountering each experiment, Stitch's human friend and partner Lilo gives the experiment a name just as she gave Stitch his name. The two then attempt to rehabilitate the experiments and find a purpose for them on Earth that suits their specific abilities, referred to as the "one true place" they belong.
Stitch, inspired by Hawaiian terminology, refers to the other experiments as his "cousins" and considers them all a part of his ohana, or "extended family". All of Jumba's original 626 experiments have their names and numbers listed alongside the credits in Leroy & Stitch.
Due to different experiments' original purposes, most experiments each have a unique appearance, powers and weaknesses. Though all experiments have unique capabilities and functions, most of them have some abilities in common. For one thing, most seem capable of scaling walls like a gecko (as Stitch frequently does); many are able to grow and retract an extra pair of arms and they all seem to be immune to aging, as the experiments remain the same while Lilo and the rest of humanity age 20 years in "Skip".
It is also shown that some experiments' powers (such as Mr. Stenchy (254)'s cuteness, and Checkers (029)'s hypnotic effect) do not affect other experiments, possibly so that these powers do not prevent other experiments from carrying out their primary functions.
It is also shown that when an experiment is dehydrated, they will deactivate and turn into a small orb called an experiment pod. If an experiment pod gets wet, the experiment will be reactivated and released. According to Jumba, a home food dehydrator is the only known method of deactivating an experiment a second time.
Upon each experiment's creation, their molecules must be charged. If an experiment's molecules are not fully charged, about a year after their creation, they will suffer glitches, during which they will experience seizures and temporarily revert to their original programming. If the molecular charging process is not completed, these glitches will eventually burn out the experiment's circuits, killing them.
The first digit of the experiment numbers reflect what series of experiment they belong to. The official series of experiments, as stated by Jess Winfield, one of the executive producers, are as follows:
- 0-Series: Jumba's test batch, including many household helpers.
- 1-Series: Civic disturbances.
- 2-Series: Technological and scientific.
- 3-Series: Psychological.
- 4-Series: Military.
- 5-Series: Elemental manipulators.
- 6-Series: Battlefield or doomsday experiments with galactic implications and world-ending properties.
For the most part, the colors of the experiment pods correspond to the series numbers; however, some of the pods are colored incorrectly.