Invader ZIM - Season 1 - Eps 33: GIR Goes Crazy and Stuff
When Zim attempts to taint the Earth’s cow-meat supply with sewer water is ruined because of Gir’s antics, he decides to increase the power on Gir’s behavioral modifier, which will permit him to stay in serious mode all the time. However, when the serious Gir starts to consider Zim a threat to the mission and runs off to learn things on his own accord, it’s up to Zim and Squidman to find Gir and turn down the power on his behavioral modifier before too many individuals see them and jeopardize their mission.
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)