Trapped for centuries in an icy tomb, the massive walrus was awoken from its ancient slumber when gigantic rockets were implanted on the North Pole to move the Earth away from the oncoming rogue star Gorath. Awakening with a thirst for carnage, Maguma lashed out at the base and damaged it before retreating back into its home valley. Knowing something was going on that involved a ravenous monster, a VTOL craft was dispatched to handle the creature. The ship buried the walrus under hundreds of tons of rock, but even this couldn't kill the monster.
Maguma stars as the antagonist. Maguma's roar was basically a elephant's roar, but was deepened and slowed down.
Just like Ebirah, Maguma was originally of Godzilla's allies for Destroy All Monsters, but was replaced, by Gorosaurus, Minya and Anguirus.
Maguma often appears in the Toho Kingdom Toons.