Three Little Witches and the Spooky Old House

A trio of witches needs a place to brew their magic, and the spooky old house down a dark road looks just right. It's full of hairy scary spiders, musty dusty ghosts, creeeeeeaky floorboards, and shivery curtains. But as the witches work, the house seems to grow warmer and brighter. Just what kind of spell are these little witches casting?