|“Mud Monsters converge!”|
|— Lord Garmadon|
Mud Monsters are strange creatures found in the Realm of Madness. As their name suggests, they are large monsters that appear to be covered or made out of mud. To catch their prey, they smother them with their bodies.
They are similar in shape to the Rock Monsters from the LEGO Power Miners theme.
Lord Garmadon summoned the Mud Monsters to defeat Sensei Wu during their fight. Just before he was completely enveloped, Sensei Wu revealed that Lloyd was in trouble, causing Garmadon to rescue him from the Mud Monsters in order to learn more about his son's predicament.