The Enchanted Manhattan Forest is the forest from the fairy tale "Hansel and Gretel" which was home to the witch's Gingerbread House and temporarily appeared in Manhattan.
After Slimer hid a fairy tale book under the Ethereal Solidifier and inadvertently activated it, the machine made the Enchanted Forest a reality in a few hours. It sprung up somewhere in Manhattan between buildings. The Ghostbusters were called in to investigate the occurrence. Once Egon Spengler confirmed negative readings, the guys headed in and passed through trees with spooky faces on them and discovered the Gingerbread House. The house and forest were reduced to smoldering piles of solid mass after the Ghostbusters blasted it with their equipment.