Spiny Shell

The Spiny Shell (, Spiny Shell), popularly known as the Blue Shell, is an item from the  series.

Origin
The Spiny Shell made its debut in  and has become an important recurring item in the Mario Kart series. It is a blue variant of a, which, when thrown, will plow through everything in its path while chasing the racer in first place.

 granted the Spiny Shell wings, which increased its speed but removed its ability to strike anything in its path, while also changing its behaviour to circle its target upon reaching them and detonate in a large explosion (similar to that of a Bob-omb, but blue), more punishing than a normal shell. It also became much more common an item, leading to a notorious reputation, though its damage could be avoidable with a well-timed or Star.

 reverted the Spiny Shell to being a very rare wingless threat to everyone in its path, but keeping the explosion at the end. Later,  introduced the item specifically to counter the Spiny Shell.

Other Mario spinoff games have borrowed the Spiny Shell for their own purposes. Its primary trait is generally that it targets whoever is in first place, often with a harsher penalty than a normal setback.

Overview
The Spiny Shell debuted as a throwing item in Super Smash Bros. 4.

When thrown, the Spiny Shell targets the current highest-ranking opponent: the fighter with the most points in time matches, the most stocks in stock matches, or the most coins in coin matches. If multiple opponents have equal standing, the one with the least damage is picked, and if multiple opponents also have equal damage, the one closest to the thrower is picked.

The Spiny Shell flies to and hovers above its target, continuing to follow above them for five seconds, and then slams down onto said player. The Spiny Shell explodes upon hitting an opponent or other hurtbox during its attack, which deals 28% damage with sizeable knockback. The time it takes from falling on its target to exploding is randomized, which can potentially make the attack difficult to dodge.

When the Spiny Shell is slamming, its explosion triggers as soon as it hits a player or hurtbox. Hence, it is possible for the Spiny Shell's target to avoid its attack by hiding under other players, so that another player takes the hit of the Spiny Shell. If the player being targeted is KO'd before the shell can attack, it will explode on the spot without trying to target anyone else.

While the Spiny Shell is flying and hovering, opponents making contact with it will be hit for light damage. This can potentially force an opponent other than the target to be hit by the shell's explosion attack if they are trapped by the hovering hits.