Spectral Mass

The Spectral Mass (also known as The Collective) is a mass of ghosts that reformed after Robo-Buster dispersed them

Robo-Buster "destroyed" the giant mass after its initial manifestation above Central Park but it later appeared at Grossjuck Plaza. The mass wanted revenge on Paul Smart, the one who unleashed the Robo-Buster on them. It tried to zap at the creature, but it kept on reforming after parts of it were destroyed. One of the ghosts then possessed Robo-Buster but was exorcised by the Ghostbusters. They eventually defeated the Giant Mass Ghost by laying out several traps and catching all of the ghosts that made up the huge phantom. Robo-Buster also helped after Egon adjusted his proton cannon arms to work like regular proton guns. Peter Venkman managed to wrangle Slimer free during the battle. About 10 traps were used in total.