A huge kidney stone covered in sharp spikes with a single exposed eye as a weak spot. She is very protective of her young and would kill anyone threatening them. She also has a very short temper, using violent threats towards Fern and her son. As Fern unknowingly caused the death of her young, the two get into a fight after Kidney Stone Mother kills Nobody Nose. She is eventually defeated after Fern stabs her in the eye with a stick covered in Ded-stone Fogger liquid.
Kidney Stone Mother's abilities include: impaling spikes, floating, spike manifestation. Her internal cavity glows purple when manifesting spikes.
She was apparently Jay's archenemy prior to meeting Fern. Having killed him many times and news that Fern killed her scared Jay very deeply of Fern.
First appeared in the Awful Hospital comic as a boss battle.
- She uses her offsprings as an attack during her battle.