|Baleful Swamp Monster|
|List of all creatures|
The Baleful Swamp Monster is a giant, vicious creature made of mud and sludge. The monster was created when Mumm-Ra fired the magical beams of the Totem of Dera into the toxic waters of Baleful Swamp. The body of the monster is made up of dark green mud and sludge. It has bloody red eyes and sharp teeth and is immensely strong.
After Mumm-Ra armed the Mutants with the Totem of Dera, they set a trap for the ThunderCats at the Baleful Swamp. When Lion-O, WilyKit, and Snarfer arrived in the ThunderClaw, Vultureman used the Totem's power to bring to life a giant serpent which attacked the three Cats. Then Mumm-Ra brought to life the Baleful Swamp Monster to attack the ThunderCats. Due to it being made entirely of mud, none of the ThunderCats weapons had any effect on it. Eventually the ThunderCats used the Sword of Omens to break Dismal Falls and cause a flood of water which washed away the monster.