Blue Spiny Shell

The Blue Spiny Shell is an item that debuts in Mario Kart 64. Although it can either appear with or without wings, its purpose remains the same. It targets the player in 1st place to help balance out each race. The winged form does not hit other racers on its way to 1st place, while the wingless form does. In Mario Kart 8, the Super Horn was introduced to destroy the item. In Mario Kart: Revenge of Snaking, a similar variant known as the White Spiny Shell is introduced.

Description
In earlier games, the Blue Spiny Shell was basically a blue version of a regular Spiny Shell. However, in more recent appearances, it is a blue Koopa Troopa shell with spikes on its hexagonal plates, and it may occasionally have a pair of wings.

Koopa Kart 64
The Blue Spiny Shell makes its Koopa Kart series debut in Koopa Kart 64, where it can be obtained from 4th to 8th place, though it is the second rarest item in the game behind the Lightning, and only human players can obtain this item. Once fired, it will travel across the ground, hitting other players in its path on its way to the leader. Once it hits the leader, it will send them flying. It will be destroyed if it hits a wall.

The Blue Spiny Shell can be held behind the kart, though it can only be thrown forward.

Koopa Kart Advance
The Blue Spiny Shell returns in Koopa Kart Advance, serving the same role as in Koopa Kart 64, though the shell has a darker blue color. It is easier to avoid, as it will fall into bottomless pits. Like in the previous game, it is obtainable from 4th to 8th place.

Koopa Kart: Double Trouble!!
In Koopa Kart: Double Trouble!!, the Blue Spiny Shell has a pair of wings that allows the item to fly instead of traveling on the ground. Once it finds its target, the shell hovers behind the vehicle and charges into it. This is the first game where the Blue Spiny Shell explodes on impact, tossing the player into the air like it did in the previous installments. This time, however, it will leave the player itemless. Just like the previous two installments, it is available to players from 4th to 8th place.

Koopa Kart DS
The Blue Spiny Shell retains its Koopa Kart: Double Trouble!! function in Koopa Kart DS. It flies while following the road to reach the leader, only then does it circle above the racer and dive onto them. It will then explode on impact, sending the vehicle flying upward and destroying any items in its possession. The explosion can be avoided using invincibility items like a Star, Bullet Bill, or Boo, the skillful use of a Mini-Turbo, or by hitting a Banana or Fake Item Box at the correct timing. The range for this item ranges from 4th to 8th place.

Koopa Kart Wii
The Blue Spiny Shell retains its function from Koopa Kart: Double Trouble!! and Koopa Kart DS in Koopa Kart Wii. The explosion can be avoided using invincibility items like a Star, Bullet Bill, Boo, or Mega Mushroom, getting shot out of a cannon, or dropping a Banana at a very precise time during a drop after the jump. The third method causes the Banana to collide with the Blue Spiny Shell and spare the target. Starting from this game, the player can use a well-timed Mushroom to escape the explosion. Due to the addition of 16 player racing per track, it can be obtained from 5th to 11th place.

Koopa Kart 7
The Blue Spiny Shell makes its next appearance in Koopa Kart 7. It starts off wingless and travels on the ground when thrown, allowing it to hit other players. Once it passes the second place racer, it will grow wings and fly to the racer in 1st. The shell is also larger than in previous installments, giving it a bigger hitbox. As the game goes back to 12 player racing, it is obtainable from 4th to 8th place.

The Blue Spiny Shell can be avoided by dropping out of 1st place at the right moment, falling off the course, using invincibility items like a Star, Bullet Bill, or Super Mega Mushroom, getting shot out of a cannon, hitting items like a Banana or Fake Item Box at the correct timing, or boosting with a Mushroom. Players who are behind the leader can avoid the shell by swerving out of its path.

The Blue Spiny Shell cannot travel further than a set distance, as it will disappear if it exceeds the distance.

Koopa Kart 8
The Blue Spiny Shell retains its properties from the previous game in Koopa Kart 8, though it has a brighter, royal blue color. It retains its wings from the moment it is thrown, though it flies much lower to the ground and can hit other players, similar to the previous game. Like in Koopa Kart Wii, it can be obtained from 5th to 11th place.

The Blue Spiny Shell can be avoided in the same ways as in Koopa Kart 7, though the player can now outrun the shell while in 1st place.

Like in Koopa Kart 7, the Blue Spiny Shell can only travel a certain distance before it disappears.

Koopa Kart Tour
The Blue Spiny Shell returns in Koopa Kart Tour as Blue Spiny Koopa and Ludwig von Koopa's Special Item, serving the same purpose as in Koopa Kart 7 and Koopa Kart 8. As usual, it is obtainable from 4th to 8th place. It can now be destroyed with the newly-introduced Super Horn.

Trivia

 * The Blue Spiny Shell is one of few items to be removed after appearing in multiple installments, appearing in fifteen games prior to its removal. Its replacement is the Spiny Bombshell, which is a stronger version of the item.