The spiny shell, also known as the blue shell, is a power-up item in the Mario Kart video game series. Originating in 1996's Mario Kart 64 and featured in every main entry of the series since then, the blue shell, when used, aims directly at the racer in first place, stopping them on impact. The blue shell acts as a "catch-up" mechanic, with racers ranked towards the bottom having a better chance of it spawning when driving into item boxes, giving them a better chance at diminishing the lead of the racer in top position. In addition to the Mario Kart series, the blue shell appeared in the Super Smash Bros. series from 2001's Melee onwards, and in Mario Hoops 3-on-3.
