Fungus

A horse's foot is one of the most important parts of its body. When it comes down to it, the foot bears all the weight of the horse, and the pressure exerted by the force of its movements. Needless to say, the hoof is a crucial part of the horse's body, which makes it a bad thing when the hoof is anything less than perfectly healthy.

This is a cool shot of George's legs. The purple stuff is a substance called ThrushBuster, and it helps kill fungus in or on horse's feet.