Tank (Lilo & Stitch)

Tank, A.K.A. Experiment 586, is an illegal genetic experiment created by Jumba Jookiba. He is designed to eat metal and grow exponentially larger with all that he consumes. He was captured by Gantu, but was rescued in "Snafu". His one true place is at a junkyard eating scrap metal.

Lilo & Stitch: The Series
Experiment 586 was the 586th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to consume metal and grow exponentially bigger with each feast. 586 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, with 586's pod landing in a car's grille.

When the car was being washed down by its owner, 586's pod got wet, activating the experiment. 586 then ate the driver's automobile, leaving only the tires, and ran off.

Later, 586 devoured a giant factory that was being shown to some tourists driving in a van, and proceeded to eat metal throughout town until he grew to a large enough size to go on a rampage.

Gantu had been informed about 586 and realized he couldn't possibly catch the experiment in a containment orb, due to how large it had grown. He then prepared his ship that had a tractor beam for abducting 586.

Meanwhile, Lilo won tickets to the Elizabethan Fair and invited the hula girls (who ditched Mertle when she refused to participate with Lilo), but neglected Stitch when he told her an experiment was on the loose. Later, Stitch (who couldn't attend the fair because no "dogs" were admitted) teamed up with a lonely Mertle in hopes of stopping 586.

The humongous 586 pursued Stitch and Mertle in Nani's dune buggy, eating another driver's car in the process. At one point, Stitch and Mertle got abducted by a tractor beam into Gantu's ship. Although Gantu was discouraged that he didn't capture 586, he locked Stitch and Mertle in holding capsules and prepared to try again.

Experiment 625 was inexplicably fascinated by Mertle, and the latter used this to her advantage by smooth-talking Reuben so that he would release her from containment. Mertle then locked Reuben in the holding capsule, freed Stitch from the adjacent one, and escaped Gantu's ship with Stitch to find and capture 586.

However, due to his enormous size, 586 proved impossible for Stitch to defeat, despite his best efforts. When Gantu later arrived in his ship and attempted to capture 586, the former was thwarted by Lilo, who brought down Gantu's ship and impeded his progress.

586's rampage continued to spread, where, after an attack on Stitch, he was abducted via a tractor beam from Gantu's hovercraft. However, Lilo had requested Gantu to get 586, named Tank, away from Stitch, since the latter appeared to be outmatched.

Shortly after Tank's defeat, Mertle broke off her temporary friendship with Stitch when the hula girls decided to take her back, and Lilo made amends with Stitch.

Tank reappeared in "Snafu", and was freed along with Gantu's other captive experiments by Lilo, Stitch, and several other experiments in a rescue mission.

Leroy & Stitch
The first 624 experiments, including Tank, 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.

Tank participated in the following battle between the experiments and the Leroy clones by eating attacking Leroys.

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 `Oe", which caused the Leroy army to shut down due to the original Leroy's fail-safe.

Trivia

 * Tank has shrunk from a massive size back to his normal size between his episode and "Snafu", suggesting that he returns to his normal size after a while without eating any metal.
 * Tank's pod color is blue.
 * Tank is described by the experiment computer screen as, "Experiment 586. Primary function: Metal consumption. The experiment becomes bigger with everything it eats."
 * Tank's ability to grow from eating metal is similar to Fudgy's ability to grow from eating chocolate.
 * Tank appears in the online game Lilo & Stitch: Alien Interception along with Plasmoid, Dupe, Clyde, Yang and Hämsterviel.