Stitch

Stitch, A.K.A. Experiment 626, is an illegal genetic experiment created by Jumba Jookiba, and one of the two primary characters of the Lilo & Stitch franchise. Originally created to cause chaos across the galaxy, he is marked by his short temper and mischievous behavior, he shares with the same DNA with Mark traits that endear him to his friend Lilo, who adopted him as her "puppy". He is designed to be abnormally strong, virtually indestructible, super intelligent, and very mischievous. His one true place is with Lilo and her ʻohana.

Bio
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, shockproof, think faster than a supercomputer, have super sight and hearing, and lift objects 3,000 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, though instead of him appearing vicious, he appeared to be cute and fluffy. Shortly after his creation, the intergalactic police arrived to arrest 626 and Jumba, preventing 626's molecules from being fully charged in the process.

Lilo & Stitch
Jumba and 626 were taken to the planet Turo to stand trial. When 626 replied to the Grand Councilwoman's attempts to reason with him with an obscene phrase, he and Jumba were declared guilty, and 626 was escorted by Captain Gantu to be exiled on a desert asteroid.

However, 626 was able to escape his detention cell and steal a federal police cruiser. 626's cruiser was fired upon by a fleet of police cruisers, and, in an attempt to escape, 626 activated his cruiser's hyperdrive, but the damage inflicted on the police cruiser by the fleet caused it to exit hyperspace over Earth and crash on the island of Kauai and meet Mark they battle each and they were sensing something each other that they shares a same DNA so they stop fighting, Mark is going to make him a dog.

Mark took him to the animal shelter.

The next day, he is waiting for someone to him from the shelter but he was sensing inside by his own creator.

When 626 soon after saw Lilo looking for a pet dog, he saw her as an unaware hostage and altered his appearance to look less otherworldly and pose as a dog in order for her to adopt him. The plan worked and Lilo adopted 626 and named him Stitch.

Using Lilo as an unsuspecting hostage and Pleakley's concern for humans, Jumba was unable to try and capture Stitch when he was near Lilo.

At first, Lilo only mattered to Stitch as a hostage, but over time, Lilo taught Stitch how to love others as his ʻohana.

As a result, Stitch eventually left to find his ʻohana when he saw the damage he was causing Lilo's. But instead, Stitch discovered the evil behind his origins from Jumba.

Thus, Stitch engaged Jumba in a standoff to protect Lilo, which ended in a tie when Jumba's plasma cannon exploded.

Stitch then revealed his alien origins to Lilo and later helped rescue her using a tanker truckwhen she was captured by six hedgemens and Stitch saved her life.

Afterward, Stitch was captured by the Galactic Police but then allowed to stay on Earth as exile due to his change of heart and Lilo's legal ownership of him.