Mr. Toad Infinity Disc

Infinity discs are placed on a Disney Infinity base station to give a character special abilities. The discs comes in two shapes: a circle or a hexagon. The circular discs are placed under your character to give that character special powers. So you get the idea, here are two characters on an Infinity base station (which works with game stations such as the Wii, PS3, and XBox 360):

Disney Infinity 2.0 Base

The hexagonal discs, like the Mr. Toad's Motorcar disc, take the place of your playset piece and give you toys for your toy box. Mr. Toad's Motorcar even has an ejector seat!

Mr Toad's Motorcar Infinity Disc

Mr Toad's Motorcar Infinity Toy Box

You can read more about the Disney Infinity Base, characters, and discs on the Disney Wikia page.