Zark is a barren planet in the Spaceman Spiff universe. Spaceman Spiff was captured there and was about to be sacrificed to the alien god Nollij. The fantasy alludes to Calvin's poor attention span in class.
Landing on the Planet
Not much was said about him landing other than that he did not crash as per usual; whether he ran out of power or landed for exploration purposes is unknown. On the planet, Spiff heads toward a canyon, where he comes across alien footprints.
Capture and Escape
Once captured, Spiff was taken to the Zark Fortress. He was to be sacrificed, but escaped by means of his Atom blaster. He ran down empty corridors (actually school hallways), and escaped out the school doors. He got to his ship and flew away. Back at his house, he lied to his mother regarding why he was home so early, claiming that there was a gas leak at the school. Calvin's mother called the school, which had the effect of getting Spaceman Spiff chased by a Zark enforcer vessel.