Meega is a blue alien genetic creation standing between 3 and 3.5 feet tall, weigh 120 lb and strongly resembles a koala, though he's referred to as a dog throughout much of the franchise. He has a limited ability to change his physical appearance, as he can retract a second set of arms, his antennae, his claws and the three spines on his back into his body Experiment 626 was the 626th genetic experiment created by Jumba, and the first to be made without Hämsterviel's funding. He was designed to be virtually indestructible, fireproof, bulletproof, think faster than a supercomputer, have super sight and hearing, and lift objects 3000 times his own weight (but not an ounce more). He was created by Dr. Jumba Jookiba from six or more of the galaxy's deadliest predators. Shortly after his creation, the Intergalactic Police arrived to arrest 626 and Jumba, preventing 626's molecules from being fully charged in the process..
Before Stitch was rehabilitated, he was a vicious and extremely aggressive and mischievous creature.
After Stitch was rehabilitated, though his mischievous and destructive tendencies remained, he possessed a heart of gold.
He also seems to like turtles, being there is a picture of Stitch shading two sea turtles in the credits of the original Lilo & Stitch movie and snuggling a stuffed turtle after a nightmare in Lilo & Stitch 2: Stitch Has a Glitch. As well as having a soft spot for turtles, he also seems to like frogs. He gently move frogs out of harm's way constantly and seems to talk to them as if they are his friends. These likes may be a sign that Stitch may be growing fond of earth creatures.

Starting off bad as he was programmed by Jumba Jookiba, Stitch was originally designed to create pandemonium and chaos wherever he was. He was also designed to steal people's left shoe, but Lilo changed his ways a while after adopting him at an animal shelter.

Stitch is still prone to having temper tantrums when things don't go his way or he sees that he's been squirted by the water bottle for something that he thought was good. So he's not all good all of the time. Or more accurately, he isn't well-behaved all of the time. He also gets easily angered by inanimate objects, especially the toaster. The toaster has popped toast in his face once and since then he has beaten up the toaster and juiced it at least twice.

The last thing about Stitch's personality is that he's got a huge appetite and gets angry if he doesn't get what he wants to eat.

One of Stitch's few weaknesses is water; he cannot swim and will easily drown due to his great molecular density. This weakness also lead to Stitch developing hydrophobia (a phobia of water). It is also shown that if Stitch consumes two different elements that form to create a particular chemical compound, all of his physical training will be wiped. As Stitch is also 62% Snootonium, if this Snootonium is drained from his body, he will become temporarily exhausted from dehydration. Stitch is being allergic to sauerkraut.