Only a Priest of Fo can cast this spell
Genesis can be cast on zombies and has a chance of harming or killing them by removing the evil presence within the creature. This gives them an internal damage wound between 50 and 120 damage depending on the power of the cast, which ignores armour (but not other damage reduction, such as from Body Strength).
It can also be cast on animals to remove any bad traits they may have. It will remove 1 bad trait per cast and always the 1st one mentioned when examining the animal.