The Twilight Zone, Season 5

Rod Serling:
The name is Grady, five feet short in stockings and boots, a slightly distorted offshoot of a good breed of humans who race horses. He happens to be one of the rotten apples, bruised and yellowed by dealing in dirt, a short man with a short memory who's forgotten that he's worked for the sport of kings and helped turn it into a cesspool, used and misused by the two-legged animals who've hung around sporting events since the days of the Coliseum. So this is Grady, on his last night as a jockey. Behind him are Hialeah, Hollywood Park and Saratoga. Rounding the far turn and coming up fast on the rail - is the Twilight Zone.