Because real human skulls are expensive (I own two), these are the 'Vince' laser-cut cardboard human skulls. You put them together yourself, and cost $40 for a 2.5" version, and $100 for a 6" version. Just don't go using one in a potion that calls for a real skull or it's going to wind up backfiring. POTION RULE #1: NEVER SUB INGREDIENTS. You see this? "The place where your penis used to be?" Yep, I was mixing up an all-night boner tonic and tried using KFC Original Recipe instead of bat wings.
Keep going for the color options including ALTERNATING BLACK AND WHITE.
Thanks to David M, who agrees there's nothing quite like holding a human skull in your hand and looking through the holes were the eyes used to be.