The Cosmic Game Room was a satellite base of operations of the Grandmaster from where he and the Challenger oversaw the contest between their teams, the Lethal Legion and the Black Order, respectively. From the Cosmic Game Room, the Grandmaster and the Challenger activated the Pyramoids, whose purpose was to be seized by either team to score a point. When somebody touched a Pyramoid, they were teleported to the Cosmic Game Room and remained encased in a crystal.
The Cosmic Game Room additionally housed the World-Engine, a device which mantained an energy envelope keeping the Earth at the correct rotation and temperature, since the planet had been abducted from its location in the Solar System to a galaxy faraway for the purpose of the contest. After killing the Grandmaster for cheating, the Challenger endangered the stability of the World-Engine to destroy the Earth.
- Appearances of Grandmaster's Cosmic Game Room
- Minor Appearances of Grandmaster's Cosmic Game Room
- Media Grandmaster's Cosmic Game Room was Mentioned in
- Images featuring Grandmaster's Cosmic Game Room
- Location Gallery: Grandmaster's Cosmic Game Room