Lilo & Stitch: The Series (2003)

S1E15 Tank

The Hula Girls have chosen Lilo over Mertle, leaving Lilo to spend time with them at the Kauai Medieval Festival, which results in her neglecting Stitch. Meanwhile, when Experiment #586 is unleashed, Stitch finds himself in need of a partner for the mission. Surprisingly, he joins forces with Mertle. As they work together to catch the metal-eating creature, they unexpectedly enjoy their time, but their fun is cut short when the creature wreaks havoc at the festival.