According to the plot of Godzilla vs. SpaceGodzilla, SpaceGodzilla is an alien clone of Godzilla. Godzilla's genetic code entered into a black hole which created SpaceGodzilla. As the antithesis of Godzilla, SpaceGodzilla wants to destroy Godzilla.
SpaceGodzilla appears similar to Godzilla except for two huge crystals that grow from its shoulders. The rest of SpaceGodzilla's back is covered with smaller crystals.
SpaceGodzilla can breath nuclear fire like Godzilla. However, SpaceGodzilla's shoulder crystals create a gravity tornado against its enemies. SpaceGodzilla also uses its crystals as a defense barrier from Godzilla's attacks.
SpaceGodzilla's first and only appearance is in the 1994 film Godzilla vs. SpaceGodzilla. In the film, SpaceGodzilla nearly destroys Godzilla until the monster Mogeura aids Godzilla. Although SpaceGodzilla destroys Mogeura, the injuries SpaceGodzilla sustains are enough for Godzilla to destroy him with his nuclear breath.