Some mutations are possessed by NPCs, but cannot be obtained through play. These include:

- Fatty Hump (Dromads)

- Invisibility (Haggabah, Who Plies the Umbral Path)

- Keen Smell (Snapjaws)

- Phosphorescence (Ctesiphus)

- Sound Imitation (unknown)

Many of these mutations do not have description text yet. Some (Keen Smell, Fatty Hump) have mutation levels, while others (Invisibility) do not. Although the player character cannot gain these abilities normally, it is possible to experience their effects by using Domination, or to obtain them via the Wish command.