Reog is a traditional Indonesian dance form. There are many types of Reogs in Indonesia, but the most notable ones are Reog Ponorogo (East Java) and Reog Sunda (West Java). Although both share a similar name, there is no connection nor similar theme among these traditions. Reog Ponorogo seems to be the kind of dance drama that demonstrate physical strength and extravagant lion-peafowl mask and costumes, while Reog Sunda is a lot more like a traditional musical dance drama and comedy.
Source : http://en.wikipedia.org/wiki/Reog
Picture from Humboldt