Invader ZIM - Season 1 - Eps 5: NanoZim
When Dib finally manages to get a picture of Zim without him in his disguise, Zim formulates a plan to shrink himself down into a microscopic size to get into Dib’s body and perform a brain wipe to prevent him from remembering where he located the picture. Fortunately for Dib, his father has been working on some technology that may just help Dib stop Zim before it’s too late, though he’ll been to be careful because he’s extremely vulnerable due to the fact that Zim is inside of him.
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)