"A tiny humanoid with leathery batwings, a barbed tail, and sharp, twisted horns flutters at about eye level, winking into sight from out of thin air."
Imps are craven, but not so timid as to pass up an opportunity for a surprise attack using their invisibility and alternate form ability. In its natural form, an imp attacks with the wicked stinger on its tail. It quickly flies out of reach if a foe manages to strike back effectively.
Not to be confused with quasits or mephits.