Blue Spiny Shells, also known simply as Blue Shells and Spiny Shells, are deadly items in the Mario Kart series. They are known to be explosive Koopa Troopa shells similar to Spiny Shells. Their special maneuver is to follow the leading player via flying to him, and then flying right into him/her. They could only be evaded with a boost of the Power Slide: the player need to be fast and must be good at timing. In earlier games, they hadn't wings, and will attack every player before the user. When they hit a victim, they will continue their path, going to the following, until reaching the leading.
They are NOT confused by Blue Shells: spikeless and wingless Koopa shells used as a Power-Up rather than a weapon.
The Blue Spiny Shell will be an item in SSBC.
- In RedYoshi's Universal Conquest, King Cloud's Lakitu Cloud can spit out Blue Spinies Shells, something regular Lakitu Clouds can't do.
- In Super Mario Ruby Quest, A Spiny Blue Winged Shell is a wearable item, enabling Mario to throw Spiny Blue Wingless Shells at enemies, and hover lightly. When he ducks, if an enemy bumps into his shell, the enemy will die.