This bridle is hands-down the most unusual I have ever seen. This Cambodian horse is wearing a bridle and breast collar embroidered with hundreds of beads. Most spectacular is the large mirror centered on the forehead!
In some cultures, mirrors are thought to reflect away evil, and I suspect that is the origin of this design. Ornamented ponies wait near tourist spots to give rides; the photo is part of a series taken near the famous temples of Angkor Wat.
The original photo is part of Magalie L'Abbe's photostream on flickr.