Amulet of Spell Shield



Blocks a negative spell that an enemy casts on the Hero once every 40 seconds.

Source
Malfurion, Tyrande and Maiev can find one in Balancing the Scales, chapter 5 of the Frozen Throne sentinels campaign, Terror of the Tides.

In the RPG
This hemispherical disk is made of an unknown material that is not quite metal, but seems just as sturdy and solid. The translucent surface appears to swirl and dance with vibrant colors hiding deep within its body.