Lilo & Stitch: The Series (2003)

S2E19 Shush

Lilo unintentionally triggers Experiment 234, which is created to eavesdrop on enemy discussions using its tail. After mistakenly hearing a snippet of a conversation, Lilo believes Mertle despises her friends, landing herself in a difficult situation. In a fit of rage, Mertle decides to assist Hamsterviel in capturing experiments, further complicating matters.