Does anyone know the name of this movie? I think it was set in a haunted house. They were having a fancy dress party. One of the men was dressed as a bumble bee and got stabbed through a vent in the floor. One of the women got possessed and started killing people. At the end she was killed by onother woman then that woman got possessed. She was put in an ambulance with onother woman who started screaming and didn't want to get in as she knew the woman was possessed.

Killer Party (1986) (http://www.imdb.com/title/tt0091338/)