Trash Alien Planet

Trash Alien's Planet was an unnamed planet that had been colonized by Trash Alien for use as a secret hideout. He built a massive door that would open for his ship and close behind him into the planet's crust. Blasternaut persued him here in order to rescue Spot, who Trash Alien had kidnapped. It is unknown what became of the planet afterwards. ("Math Blaster Episode 1: In Search of Spot")