From CloudModding OoT Wiki

The Running Man is a reoccurring Npc in the Zelda series. In Ocarina of Time, the Running Man will buy the Bunny Hood off of Link, while as an Adult the Running Man will claim to run a race against Link, but always beat Link by exactly 1 second. He's a hell of a lot easier to race against in Mario Sunshine though.

In Twilight Princess, you can lure the Running Man off of a cliff. However, he will still have the last laugh since doing so will slow the game down to a speedy 1 FPS.