A diseased named for its symptoms, Peelhoof causes uncontrolled growth in the horny tissue that makes up hooves of animals in Nymm. Often large chunks break off after it grows too brittle. The hooves become ingrown to an extreme extent until the hooves actually cause the lower foot to fall off. This auto-amputation is caused when the ingrown portions cut into the ankle too deeply and cause repeated infection and irritation that stymies blood flow and causes necrosis in the foot until it rots off. The horses can technically survive the process and recover, but lack feet and usually eventually die because they cannot feed themselves or move.
Oddly, goats are unaffected by the disease. Some have even suggested that goats invented the plague to secure their position in the world. While that’s probably nonsense, goat populations have certainly exploded, as they are the most reliable livestock now.
Some blame a mythical figure named Krillvaga Twice-Cursed for the disease. This holds no real evidence however.