That's his nickname at the track. It's been my nickname for him since he was a baby, and Erin told Dave (one of the parents and the announcer for the races), and he's used it during race ever since when he's talking about Bren. At first Bren wasn't too happy about it, but it's grown on him and he actually considered putting it as his nickname on his Hyperforce jersey.
Anyway, he's doing so well with racing. He's taken first place for 12 straight races now, and he'll be advancing to expert before too much longer.