The Grandmatriarchs first appear when you purchash One Mind, resembling normal elderly women. However, as the Grandmapocalypse continues, the Grandmatriarchs get more decrepit and eldritch, eventually settling on slug-like creatures made of flesh and dough. They have multiple stages, starting from "Awoken" then to "Displeased" and then to "Angered." If stopped with the Elder Pledge/Covenant, they go to "Appeased." The Grandmatriarchs also summon Red Cookies in place of Golden Cookies. They can only be stopped with the Elder Pledge for half an hour, or permenantly with the Elder Covenant. They are based off of Lovecraft's works, such as Yog-Sothoth or Cthulhu.