NOTE: I used Great Value Fondant - white - found at Wal-Mart, and Wal-Mart Neighborhood Market stores. It worked just as well as the other Brands, was easy to use, and handle, rolled out like a dream, and held the Ghosts shape. When working with Fondant, a cool setting is best; if it's hot, the Fondant will droop. If you're not serving the cupcakes as soon as you assemble them, I would suggest not cutting the Ghosts out until 3 hours before serving the cupcakes, and leaving them on the parchment paper in a cool place, but NOT the refrigerator. The Fridge tends to dry the Fondant out, and it will crack, and that won't be a good look for your Ghosts. You can Frost the cupcakes ahead of time, and put the Marshmallows on the frosting, and place the cupcakes in the refrigerator. When you're ready to serve the cupcakes, roll out the Fondant like the instructions above state, and cut out the Ghosts; this can be done up to 3 hours ahead of time, then just place the Ghosts over the marshmallows, add the eyes, and serve. Enjoy!
ALSO: If your Fondant Ghost is a little too long after you drape it over the marshmallow, simply snip off the fondant around the bottom of the Ghost, so that the swirled frosting is visible.