Invader ZIM - Season 1 - Eps 6: Germs
After Zim watches an old movie where some invading aliens are defeated by some bacteria, he begins to study germs more. However, when he discovers that such germs truthfully are everywhere, he begins a crusade to kill every germ in his headquarters so that he can be safe, which is helped by the fact that Gir had some cleaning spray handy in the house; though when the cleaning bottle runes dry, Zim must attempt to go to the store and get some more, despite the fact that he knows just how many germs are out there.
About Invader ZIM

Title: Invader ZIM
First Air Date: 2001-03-30
Last Air Date: 2006-08-19
Status: Canceled
Rating: 8.429/10 (from 392 votes)
Language: EN
Seasons: 3
Total Episodes: 46
Network: Nickelodeon
Genres: Animation, Sci-Fi & Fantasy, Comedy, Kids
Production Companies: Nickelodeon Animation Studio
Synopsis
Zim dreams of greatness. Unfortunately, though, he's hopelessly inept as a space invader. Desperate to be rid of the annoying Zim, his planet's leaders send him on a mission to infiltrate Earth, providing him with leftover, cobbled-together equipment. To their consternation, Zim succeeds in setting up a base on Earth and infiltrating human culture, posing as a human child as he plots the planet's downfall. Only Zim's archnemesis, Dib, recognizes that Zim is an alien, and of course, nobody believes Dib's claims.
Cast

Richard Steven Horvitz
Zim (voice)

Andy Berman
Dib (voice)

Rosearik Rikki Simons
GIR (voice)

Melissa Fahn
Gaz (voice)

Lucille Bliss
Ms. Bitters (voice)

Rodger Bumpass
Professor Membrane (voice)

Kevin McDonald
Almighty Tallest Purple (voice)