The Mud Aliens are a race of sludge-like entities who were allowed by Aku to live on Earth.
Background[]
They are seen in Episode XCIII, where they are seen paying tribute to Aku with a sludge totem in his likeness, much to his chagrin. Aku quickly remarks that they are making a mess, and tells them to leave. It is unknown how the past Aku's existence affected their existence. It is possible they never showed up to Earth due to Aku allowing them to inhabit on it.