A prostitute who is mentally challenged. The origin is traced to an incident in 1996 in Lake Doster, MI USA. During an improvised scene in a video made by a group of middle school aged friends, one of the boys was portraying a mentally challenged prostitute when he grabbed a large pasta pot and said, "Stupid pastapoot."
Kelly is getting deperate. She was acting like a goddamn pastapoot at Adam's party.