Obsidius, also known as Magmouth, is a living lava monster that appears in the 2007 video game Godzilla Unleashed, in both the Wii and PlayStation 2 versions.
Obsidius' body is composed of volcanic rock, while his insides are molten magma. Obsidius has two spikes on the back of his head, no eyes, a large mouth full of magma, two large hands, and a forked tail.
Obsidius was created by SpaceGodzilla's crystals when they entered a volcano and animated the magma inside. Obsidius emerged from the volcano and immediately attempted to make himself more powerful by harnessing the power of the crystals.
- Physical Strength - Being composed of obsidian, Obsidius' body is very hard and difficult to damage. Obsidius is also able to deal punishing attacks with his thick body.
- Lava Breath - Obsidius can spit a stream of molten lava from his mouth.
- Obsidius and Krystalak can be considered "brothers," because both were created by SpaceGodzilla when he used crystals to bring inorganic minerals to life.
- Obsidius was voted into Godzilla Unleashed by fans. He was chosen over the monsters the Visitor, Lightning Bug, and Fire Lion.