The really annoying things in mario kart that fuck you up really bad. They come in three different types:green, red(or brown), or blue. The green ones aren't so bad they just fling around stupidly. The brown ones, you should watch out for.
They seek the person in front of you and fuck them up. The blue ones automattically go to the player in 1st place.
"I was in first place, then fuckin yoshi threw a red turtle shell at me and I got fourth."