A Mountain of Giant Dinosaur Bones

This is just a PTR placeholder, right?

....Right...?

EDIT: OH GOD THEY'RE ACTUALLY SERIOUS. Better get your grinding pants on, guys. This is the new Bloodsail Buccaneers.

EDIT 2: Might as well use my top-voted spot to add some information on this task itself.

Giant Dinosaur Bones are dropped in varying amounts from all of the creatures on the Isle of Giants. Every single creature on that island is a level 90 elite, and while some are soloable, others will reduce you to a bloody smear in seconds, especially the Primal Devilsaur. Bring friends to help. The bones are a 100% drop, and the amount from a single creature varies between them, ranging from 1-2 from the Zandalari Dinomancers, to around 40 (?) from the Devilsaur. It all boils down to if you can get some people to assist you in the grind.

There are however some extra benefits to grinding off these. In particular, the [npc=69925]s drop four different pets, which due to the Battle-pet caging thing, can be sold / given away, or sold to a vendor for 60 gold apiece.

Two extra things I'd like to add. If you've not gone COMPLETELY demented by the time you get 9999, you can grind another 1000 to purchase a [item=94190] , which is a companion pet. Secondly, enduring through it will give you a Feat of Strength, I've Got 9999 Problems but a Bone-White Primal Raptor Ain't One. Good luck, everyone.

EDIT 3: As of Warlords, this is now a lot easier, and not just because of the bigger level advantage - The bones are now tradable. That being said, if you don't want to grind all the way to 9999 and have bones left over from Mists, you can always sell them for a tidy sum now.

[item=94290] Info:

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• Similar in coloring, yet distinctly different, to [item=13317] removed in patch 1.4
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• Turning in 9999x [item=94288] to [npc=70022] for A Mountain of Giant Dinosaur Bones grants mount.
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• Learning mount grants Feat of Strength: I've Got 9999 Problems but a Bone-White Primal Raptor Ain't One
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• After 1 mount learned, it can be used on any char merged on battle.net account. (As a 5 boxer, I confirmed this on 3/10/13 when I got mount)

[item=94288] Info:

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• Drop from Elites in Isle of Giants which is the island north of Kun'Lai Summit
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• Each Elite has 2-13 million health and drops 1x-44x Bones.
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• Currently stack to 999 (that's still 10x stacks of bag space reserved for this)
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• Currency for [item=94190] x1000, Spirit of Harmony x100, Mote of Harmony x10, or about 2gold x1
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• [item=94295] also drops while gathering bones. This gives a shot at additional mounts.
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• Full 5.2 Review with rare spawns and maps provided.
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Isle of Giants Elite Info:

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• [npc=69925] - 2 million health, 1-2x Bones, also drops 4x pets
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• [npc=69992] - 3.1 million health, 7-9x Bones, Growl,[spell=138768],[spell=138769]
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• [npc=69983] - 8.1 million health, 18-22x Bones, [spell=138772],[spell=138768],[spell=138769]
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• [npc=70020] - 6.3 million health, 15-17x Bones, [spell=138817]
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• [npc=69993] - 4.7 million health, 11-13x Bones, [spell=138765]
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• [npc=70008] - 13 million health, 35-45x Bones, [spell=138766]

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See all 350+ Mounts in the game: Mount Collecting: The Completionist Guide

The patience level required for this quests... IS OVER 9000!!!