Tony Hawk shows off a vial of his blood and a note verifying he's allowing it to be used in the skateboard series.

No doubt, serious skateboarders occasionally leave some of their blood behind when they take a fall. But a skateboard infused with real human blood? That's a step beyond. Skateboarding legend Tony Hawk actually donated two vials of his own blood that was then mixed in with the paint used on a limited-edition run of 100 skateboards -- and they sold out instantly.

Hawk posted an Instagram video of his blood being drawn and the blood being mixed into a can of red paint that was then applied to the skateboard. Then he worried about the skateboard owners being in possession of his DNA and shouted, "No clones!"