Inbreeding to Mr. Prospector through champions Conquistador Cielo and Gold Beauty has been rare. But in recent A. G. Vanderbilt Handicap (gr. II) winner Diabolical, the cross has proven golden and may soon glitter all the more brightly if the colt can go on to grade I glory in the Vosburgh Stakes (gr. I) or Breeders' Cup Sprint (gr. I).