After three nights in a row, coincidentally culminating on Winston Zeddemore's birthday, the Ghostbusters encountered Ghash, leader of a group of poltergeists. By feeding on the lesser entities, Ghash was able to increases his P.K.E. and gain the ability to roam. Due to a mishap at Winston's party, Slimer left the Firehouse and followed several entities to Ghash. He soon absorbed all of these entities to become unstoppable. The Ghostbusters adjusted their equipment to focus primarily on Slimer's unique frequency of 500,000 Mega Hertz and extract him from Ghash. They were then able to trap him and place him in the Containment Unit.