Frost Wyrm Skull Shield

This ancient Frost Wyrm skull has been equipped with handles, turning it into a powerful shield.

Increases armor by 2 when worn and reduces Magic damage dealt to the Hero by 33%.

Source
Kael and Lady Vashj can find this in The Dungeons of Dalaran, chapter 3 of the Frozen Throne alliance campaign, Curse of the Blood Elves.

In the RPG
This unique shield was carved from the flattened crown of a white dragon's skull. The bone has been hardened and enhanced with an intricate steel framework interlaced with unidentifiable runes from an unknown maker.