It is known to menace the Changelings and eats every plant that grow around their kingdom.
It is mentioned several times during the course of the episode, but does not appear physically until near the end of the episode.
It is described by Starlight Glimmer as "half-bear, half-mole, half-raging-pile-of-claws". The maulwurf mostly resembles a giant star-nosed mole with blue fur, large forearms, and multiple light-blue appendages around its snout. It has an extremely thick hide, allowing it to shrug off magic blasts from a unicorn, and withstand having a large chunk of rock thrown at its head.
Outside the kingdom, Starlight lays a trail of leaves to lure the maulwurf to the hive. Her plan is to have Pharynx save the hive from the maulwurf so that the rest of the changelings will finally accept him. Unfortunately, Trixie cannot find Pharynx anywhere; having overheard their earlier conversation that they were about to tell Thorax that he may have no choice than to banish his older brother, Pharynx has apparently left the kingdom on his own.
Somewhere in the desert, Starlight, Trixie, and Thorax find Pharynx battling the rampaging maulwurf on his own. They try to help him, but the maulwurf's thick hide makes it impervious to most of their attacks. Suddenly, the rest of the Changeling swarm appears to provide support, but they are unable to help much due to being out of combat practice.
Pharynx comes up with an idea inspired by how he used to tease Thorax when they were little, and the changeling brothers team up flying near the maulwurf to make the beast hit itself over and over — a blow to its face, one in the stomach, another two (one tougher) in the face, another in the stomach, and the final blow is a vicious bite in the paw —. When the maulwurf's stamina is worn down enough, it retreats underground.
- The word "maulwurf" is German for "mole", the animal on which it is based.
- The Maulwurf was mentioned twelve times during the episode:
- Six times by Starlight Glimmer.
- One by Trixie.
- Three by Thorax (one indirectly, and another one after its defeat).
- One by Pharynx.
- One by an assistant Changeling.
- The way in which the Maulwurf is shaken when all of the Changelings attack it at the same time is similar to the form of shaking of the Waterwraith from Pikmin 2, when the Pikmin attack it.
- Also, some of its roars are similar to the Waterwraith's.
- It is never mentioned if something is done about the Maulwurf after the episode.