Make fondue: Bring wine and garlic to a boil in a medium saucepan; reduce to about 1 cup. Simmer over medium heat for 1 minute.
Toss cheeses with flour. Gradually whisk into wine, 1 scant cup at a time, whisking constantly until cheese melts before adding more. Add liqueur, if using, cayenne and nutmeg; season with salt and pepper. Simmer over medium-low heat until thickened and smooth, about 2 minutes. Transfer to a warm fondue pot and keep warm.
Make Creepy Dippers: Wrap strips of prosciutto around apple to make Apple Mummies. Cut bat shapes out of bread and toast to make Bat Bread. Combine grapes in a bowl for Grape Eyeballs. Cut and blanch cauliflower florets to make Blanched Brains. Keep cheese warm and stir as you eat.