Black Shell

From the Super Mario Wiki

Black Shells are black shells of unknown origin that appear in the Mario Kart GP series. Its effects are similar to a Winged Spiny Shell, explodes suddenly when knocks on. Although unlike a Winged Spiny Shell, it can only be fired straight and is a bit more common to get. It is possible tha these are the shells of a Nokobon, as they are both black and they both explode. They can also be used as a triple if unlocked.

Some evidently high-ranking members of the Koopa Troop, such as Black Ninjakoopa and Lakithunder, are shown to wear, non-exploding Black Shells. Additionally, in The Super Mario Bros. Super Show! Koopa Troopas, Lakitu and Hammer Brothers were portrayed as wearing, as the episode "Mario and Joliet" showed, fire-proof Black Shells.

Shells
Green Shell | Giant Green Shell | Red Shell | Giant Red Shell | Triple Shells (Green · Red) | Blue Shell | Giant Blue Shell | Yellow Shell | Spiny Shell (Mario Kart) | Giant Spiny Shell | Black Shell | Bowser's Shell | Gold Shell

Mario Kart Items

Absorbing Mushroom | Banana | Basin | Birdo Egg | Black Shell | Blooper | Blue Shell | Bob-omb | Boo | Bowser's Shell | Cape Feather | Chain Chomp | Cream Pie | Driver Virus | Fake Item Box | Fireball | Giant Banana | Golden Mushroom | Green Fireball | Green Shell | Mega Mushroom | Mini Mushroom | POW Block | Peach's Frying Pan | Red Shell | Shield | Smokescreen | Star | Super Mushroom | Tacks | Thunder Cloud | Thunder Stick | Thunderbolt | Time Bomb | Triple Green Shells | Triple Red Shells