Mugg Fallow was the presumed homeworld of Mnggal-Mnggal, deep in the Unknown Regions. The grey sludge that formed the being's body (or brain) covered almost the entire planet, with only lifeless continents and the remains of fossilized trees visible. Mnggal-Mnggal filled the planet's former oceans, and ran across the continents in gray rivers.
A fleet of derelict ships formed a ring around the planet, their origins ranging across millennia. Mnggal-Mnggal used its mind-controlled zombies to pilot the ships there as macabre decoration, with Gree sailships and a treasure barge once belonging to Xim the Despot among the lifeless fleet.
The planet's location was at least known to the Chiss, who stored the information in their data library on Csilla. Other species native to the Unknown Regions such as the Croke and Lugubraa sought to destroy Mnggal-Mnggal, knowing the extreme danger it posed, but it is unknown if they knew the coordinates of Mugg Fallow.
- The Unknown Regions (First appearance)