The Mud Men are the inhabitants of the Templor cave in the Valley of lost souls on planet Mongo.They appear to be large, muscular humanoids with pointy ears and rough features.They actually are made of the magical healing mud that is found in the cave and disintegrate when exposed to water so they held one of the greatest miracles of healing but were not able to ever leave their cave.
Other adaptions[]
Mongonians whose appearance is strikingly similar to the Mud Men are depicted in the 2013 graphic novel Flash Gordon: Zeitgeist by Eric Trautmann however it is unclear if the resemblance was intended or coincidental.