Mt. Fondoom is a volcano in Marzipan City. Fondoom's lava is made of fondue, and the King of the Sky sometimes visit the volcano. Fondoom also made its first appearance on "Burple Nurples," when Mung threw the poisoned nurples to the crater, making the volcano erupt.
- Mt. Fondoom is likely the only volcano in Marzipan City.
- The Burple Nurples caused the volcano to erupt. (Who knew those poisoned foods were so strong!)