Shiroi Senshi Yamato
Outside of the ring Tetsukimen always wears an iron mask. When the dog enters the ring the mask is always removed. Underneath the skin on his forehead is a diamond which is extremely dangerous when the dog pushes the opponent over himself on its Dynamite Crasher technique. Yamato manages to remove the stone in their match and beat the dog.
See more pictures in Tetsukimen/Gallery.