This is really the pièce de résistance: You and your child can hit the drawing board together first and come up with a feasible but sufficiently scary or cute monster design. If you’re short on time or feeling stumped, you can’t go wrong with a simple set of horns. Your child’s inner monster will take care of the rest. Make sure to add some details in black to the white horns, so they look a little more defined, and parents aren’t asking you what’s on your kid’s forehead.