Inspired by the Night-gaunt from the Lovecraft mythos, this CR 6 monstrous aberration has some unique lore and mechanics that can punish your lying players or act as the start of a political questioning/turmoil arc! Imagine a sudden outbreak of Gauntmares near the King's castle as the next heir is supposedly born... What deceit and lies caused these devilish creatures to invade? How deep does the rabbit hole of lies and disillusionment go so that it could birth and sprout monstrous creatures? Or is it perhaps part of someone's greater plan to falsify royalty?
Created for my initial campaign setting, the Gauntmare is the first of many Kabni I plan to release, a new type of aberration that is the manifestation of a type of emotion or feeling. The Gauntmare in this case, represents Disillusionment, Lies, and Deception, and these beings sprout from sentient minds where this psychic energy is put out into their realm of existence.
If you're a fan of psychology, then I hope you have fun with the Gauntmare and the idea of Kabnis, but if its a little too specific and detailed for your world, then they can always just be a scary alien creature to throw at your players!