Reins of the Quantum Courser is a Very Rare drop from the final boss of the Dawn of the Infinite mega-dungeon that teaches you a mount you do not own, including Zul’gurub mounts! We’re looking at the updated list of mounts you can get.
You can learn one of the following uncollected mounts every time you loot Reins of the Quantum Courser:
Reins of the Drake of the North Wind
Reins of the Infinite Timereaver
Reins of the Vitreous Stone Drake
If you own all the mounts above, you won’t be able to use Reins of the Quantum Courser, but can trade it to other players that participated in your run.