Invader ZIM (2001)

S1E6 Germs

Inspired by an old film in which invading aliens are vanquished by bacteria, Zim becomes fascinated with germs. Realizing they're literally everywhere, he embarks on a mission to eliminate every germ in his base to ensure his safety. With Gir's cleaning spray on hand, Zim gets a head start on his germ-fighting campaign. However, when the spray runs out, he faces the daunting task of venturing to the store for more, fully aware of the multitude of germs lurking outside.