Blinky is the Pac-Man ghost who appears as a playable racer in Mario Kart Arcade GP.
Blinky originated in Namco’s Pac-Man, released in arcades in 1980. He is the red ghost and is often identified by the nickname “Shadow.” His role in the original Pac-Man is to pursue the player directly, while the other ghosts use different targeting behaviors.
Mario Kart Arcade GP, developed by Namco and Nintendo for arcades, expands the usual Mario cast with guest characters from Namco properties. Its playable roster includes Pac-Man, Ms. Pac-Man, and Blinky. That makes Blinky an unusual Mario Kart racer: he is a ghost rather than a human, animal, or mascot character from Nintendo’s core franchises.
A common mix-up is choosing Pinky, Inky, or Clyde because all four ghosts are central Pac-Man characters. However, only Blinky is playable in the first Mario Kart Arcade GP. The later arcade series changes its guest roster, so this answer is specific to the original game.