"Tank" is the fifteenth episode of Lilo & Stitch: The Series. It aired on November 10, 2003.
Lilo wins tickets to the Elizabethan Fair and invites Elena, Teresa and Yuki to join her. However, Mertle refuses to go because she does not want to be with Lilo, and Stitch is not allowed inside because no dogs are admitted. They team up to catch a metal-eating experiment. Eventually, Gantu is allowed to capture the experiment to save Mertle and Stitch. The hula girls take Mertle back, and Lilo apologizes to Stitch for neglecting him.
- Moral: It's important to have new friends, as long as you don't neglect your old ones.
- Special guest appearance by "Weird Al" Yankovic, who voices a singing minstrel.
- This episode hints that Elena, Teresa and Yuki may actually hate Mertle, as they grew sick of playing dolls with her all the time, and thus decided to temporarily hang out with Lilo.
- Lilo would have never blown Stitch's cover if she found out that no dogs were allowed at the fair.
- Mertle meets Reuben for the first time.
- Reuben is revealed to have an abnormal fascination with Mertle.
- 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.