From the Super Mario Wiki
Blooper Racers are a variety of Blooper that appears only in Ricco Harbor in the game Super Mario Sunshine. In this game, Mario must ride on one through an obstacle course run by a Pianta named the Big Daddy of Blooper-surfing, and in the harbor itself to get Red Coins. They come in three colors, each affecting their abilities:
In Episode 2 of Ricco Harbor, Mario must complete an obstacle course in 45 seconds or less while riding on the Blooper of his choice. Bumping into an obstacle or running out of time costs Mario a life. In Episode 6, Mario must ride on a Blooper to get Red Coins scattered over the water in 2 minutes or less. In Episode 10, Mario must repeat Episode 2, though in 40 seconds instead of 45. Every episode that Blooper Racers appear in is timed.