Knuckle-Headz Head Poppin™ Racers. Fueled by a powerful pull-back motor, Knuckle-Headz simulates medieval jousting with a few modern twists. Six exciting new collectible characters face off in a battle to see which can keep its head. Define the battlefield, aim your vehicle at your opponents, pull back for maximum momentum, and let them zoom toward each other. Direct hits result in the loser’s head popping off about 12 inches. Reset your spring-loaded characters head and face off again. 6 characters available in single packs.