Preheat the oven to 180 degrees.
Cream the butter and sugar together in a mixing bowl. Add the eggs, cocoa powder, baking powder and the flour gradually, folding as you go.
Prepare 12 cupcake cases in a muffin tin.
Gradually add the mixture until you have filled the cases three quarters of the way up (depending on how big you like your cupcakes) place these in the oven for 20 minutes.
While the cupcakes cool, prepare the buttercream. Mix together the butter and icing sugar with 5 crushed cookies and cream biscuits.
Pipe the buttercream onto the cupcake, and top with half a cookies and cream biscuit. Cut the remaining half into two pieces and use these as wings. For the finishing touch, add edible eyes to the biscuit using buttercream, to give your bats spooky eyes!