Pokemon dash is a Nintendo DS racing game based on the Pokémon Franchise.
Players control Pokémon in a race, just one more competition for the psuedo-animals as no real story is implemented.
Players rub the DS touch screen to guide their chosen racer around a Pokémon shaped race track, from a top down view. This game was largely considered one of the worst Pokemon spin-off games.
What made it what it was
Essentially this game was a tech-demo for the (then) newly launched Nintendo DS. It featured touchscreen only controls, adding to the experience that you are racing animals not vehicles, because you had to actually work a bit more than just pushing buttons. It also had GBA slot 2 connectivity with all GBA Pokemon games. Insterting one of these allowed you to ulock new tracks based on which pokemon you had captured on the cartidge.
Nintendo knew that the Pokemon name would move the game no matter what, so they used it as a jumping board to aclimate users to DS touch screen. Much in the same way that Nintendo uses Wii-play to "teach" the new controller scheme.