Blue shell (InstanceTopic, 8)

From Compile Worlds

A blue shell, not to be confused with a spiny shell, is a blue Koopa shell that you can wear to protect yourself from fireballs, cannonballs and {{#linkfarm|Spiny|brick block|hammer|boomerang|bone|Koopa shell|all sorts of other stuff that might get thrown at you}}. It also makes a great fashion statement and easily compliments Christmas-colored clothing. Blue shells, like many other Mario powerups come from question mark boxes. However, these guys also must comply with the strange Question mark box phenomenon, and can't come out of a QMB until you eat a Red mushroom and grow really big.

Blue Koopas and their shells debuted in Super Mario World, but the blue shells could not be climbed into by Mario or Luigi. They also appeared in New Super Mario Bros., and they are essentially a replacement of the Hammer Bros suit, which is over 9000 times more awesome than this. However, it's still nice to know that you're covered.