Taking a small handful of black fondant at a time, use a rolling pin to roll out to about ¼" thickness. If it gets sticky, use the powdered sugar as you would flour. Use a bat-shaped cookie cutter (about 4" wide) to cut out the 'wings'. You will need 24 bats in total. Use a small knife to cut them in half and place onto a baking sheet lined with wax paper. Leave them in a cool dry place (but not the fridge) to harden. This may be a few hours or several as it can depend on humidity levels.
Line 2 (12 count) cupcake pans with cupcake liners. Make cake mix according to package instructions and divide between cupcake liners. Bake at oven temperature provided on the box. Remove from the oven and let the cupcakes cool completely prior to decorating.
Once the cupcakes have cooled, add several drops of black gel food coloring to the chocolate frosting. Stir to combine.
Attach a star tip to a piping bag and scoop the black frosting into the bag.
Pipe a swirl of frosting on the top of each cupcake.
Insert the dried/hardened bat wings on each side of the cupcake.
Place two candy eyeballs onto the frosting and your cut bat cupcakes are done!