Activated charcoal is a superfine and odorless black powder. It's made from heating carbon rich materials like wood, coconut shells, peat and more at very high temperatures. It's super easy to add to this drink to make it perfect for Halloween. This cocktail would be great all year long, but adding activated charcoal to it creates an amazingly creepy drink. Even if you don't have activated charcoal on hand, this drink would probably still work well for Halloween because of the muddled blueberries, that create a rich purple hue.