Rosearik Rikki Allen Simons is an American voice actor, writer, cartoonist, and animator. He is best known as the voice of GIR in the Nickelodeon animated series, Invader Zim. Simons has also written a number of novels and comic series, often working with his wife, Tavisha Wolfgarth-Simons.

Invader Zim is an American animated science fiction dark comedy television series created by comic book writer and cartoonist Jhonen Vasquez for Nickelodeon. The series centers on an extraterrestrial named Zim, from the planet Irk, and his mission is to conquer Earth and enslave the human race along with his malfunctioning robot servant GIR. He is antagonized by Dib, a young paranormal investigator who is determined to stop Zim from succeeding.