Fragment of Deathwing's Jaw

Fragment of Deathwing's Jaw is an objective of Patricide.

Following Deathwing's defeat at the Maelstrom, Lord Itharius now resides in the Horde capital of Orgrimmar and Chromie in the Alliance capital of Stormwind, both with fragments of Deathwing's Jaw. Speaking with either of them will allow players to witness the closing cinematic of Cataclysm.

Source
This item drops from Madness of Deathwing in the Dragon Soul raid.