One who annoys you usually by invading your space to scream or yell at your ass.
Also can be used as a term to describe the general douchery of an annoying person.
Stop being an ass banshee or get the hell outta here!
One who invades the ass and/or is a complete douche bag
Guy 1: Hey man wanna see my pokemon cards!!
Guy 2: Get the fuck away from me you ass banshee!