When I first heard tell of the bananach I thought, okay, we finally have a FUN Dweller to learn about. Mayhaps a piece of tropical fruit has been hexed by some jaded warlock who needed some a droll diversion after a wearying day of research. Adventurer, prepare to be disappointed. The bananach is in fact a floating, dessicated corpse with the skull of a man and the body of some withered amphibious abomination. It's a nightmare creature that will freeze your blood with demonic magic and dance on your ruined corpse, waving its bony limbs about and bobbing up and down, not unlike a jaunty banana might. Oh! That's probably where the name comes from.
