Acquire the Horn of Banthar and return it to Hemet Nesingwary at the Nesingwary Safari in Nagrand.
Banthar is the fiercest and most elusive of all the clefthoof in Outland. She's also the hairiest.
It is said that she roams with her clefthoof herd in the Spirit Fields near Oshu'gun.
You want to truly prove your hunting mastery? Bring me her horn!