Sandboard

The sanboard is an item used by Sonic and Tails in Sonic Adventure. Sonic's is yellow with blue stripes, while Tails's is green with yellow stripes.

Sonic Adventure
In Sonic Adventure, Tails uses his sandboard to pursue Froggy through Sand Hill. If the player decides to play the mini-game with Sonic, then Sonic will use his version of the sandboard.

Trivia
In Ice Cap, there is a glitch that Sonic replaces his snowboard with a sandboard.

The only canonical use of a sandboard is in Tails's story, tough Sonic can use his if the player replays the minigame as him.