Planet Mobius (モビアス Mobiasu?, lit. "Mobius") is the main setting of the storyline for both versions of Sonic the Hedgehog Spinball. It is the planet where Dr. Robotnik enacted his scheme to turn the world's fauna into robots, but was stopped by Sonic.
On Planet Mobius, Dr. Robotnik's enacted his most diabolical plan yet by turning the Animals of the planet into robots by mechanizing Mt. Mobius into the "Veg-O-Fortress", which utilized the Pinball Defense System to eliminate intruders. Tails thus flew Sonic to the fortified mountain to collect the Chaos Emeralds and stop his plans. When they got there, Sonic went in alone and climbed the mountain from the inside while destroying Robotnik's operations, eventually defeating Robotnik at the summit and escaping with Tails.
- The name Mobius may be a reference to a shape known as the Möbius strip, a shape with no clear start or end that appears to have multiple sides, when in fact there is only one.
- It is never explained if Planet Mobius is supposed to be the usual world where the rest of the games in the Sonic the Hedgehog series take place on, or if the characters somehow traveled there.