Mini Mushroom

The Mini Mushroom is an item introduced in Mario Kart Insanity. It shrinks the user to a tiny size, allowing them to gain a speed boost, drive on water, and jump higher than usual. Its opposite is the Mega Mushroom, which grows the user to a massive size. Prior to appearing as a Mario Kart item, it debuted as a power-up in New Super Mario Bros., where it allows the player to access secret areas and run on water.

Mario Kart Insanity
"The Mini Mushroom is a brand new item in Mario kart Insanity. This item will shrink the user, but instead of slowing them down like the Thunder Cloud from Mario Kart Wii does, this item will increase their speed and their jump height, as well as letting them drive on water."