Found in the Valley of the Four Winds immediately west of the Pools of Purity, Manglemaw is minding his own business, chomping away at a few dead cranes. Killing Manglemaw spawns Manglemaw's Mother, and killing her will grant you an Enormous Crocolisk Tail. The quest it provides, a simple quest wherein you simply deliver the tail to Yan, will reward you with 129,000 experience and a bit over 10 gold.
"Fabulous prizes" may have been an exaggeration, but your alts will appreciate the bonus regardless.
Filed under: Mists of Pandaria