The Dash is able to run at super-human speeds for short distances and can grant this speed to others. The Dash's true form is the same depicted on the card: a lavender fox-like creature with purple paws, a blue gem on the center of it's forehead, and long, rabbit-esque ears. Dash is under The Windy.
The Dash appears in Episode 30 of the anime in which Rei Tachibana takes care of it at her home after it escaped Sakura's initial attempt to seal it. Rei is apparently one of the star track runners for Tomoeda Elementary. The Dash repays Rei's kindness by increasing Rei's speed whenever she ran, helping her break records and qualify for a city-wide track meet. Sakura and Syaonran were able to capture The Dash before the meet, though, and Rei was able to advance to the final round without The Dash's help. During the final round, Rei starts missing The Dash (who she named Peewee) but gathers up the motivation to finish the 100-meter dash when she sees him at the end of the track. This wasn't an illusion, but the actual Dash that Syaoran summoned.
The Dash is transformed during Episode 53 when Sakura panics when Cerberus tells her that the un-transformed cards will slowly lose their power. In response, Sakura does a flurry of transformation, but then almost faints in the middle of transforming The Dash. Stuck between the two magics of Clow Reed and Sakura, it panics and flees, possessing Touya's bike in the process. Sakura and Cerberus finally manage to follow it into the park where Sakura used The Loop to catch up to it. She then calms it down and fully transforms it into a Sakura card.
It also appears three times in the crossover series Tsubasa Reservoir Chronicle, twice in the manga and once in the anime. The first time it was a Kudan in the Hanshin Republic, then again where a tribe of Dashes tries to either eat or sacrifice Syaoran to get rid of a local monster. It appeared in Episode 30 of the anime as a sandy colored creature that Syaoran found while at the excavation site. Sakura had asked to keep it as a pet, but later in the episode it had died.