The Seal of Danzalar

The Seal of Danzalar is an epic ring. It is one of the few items with resilience that drops from a raid boss. This is a PvP/Arena ring for casters.

Source
This item drops from The Lurker Below in Serpentshrine Cavern.

Inspiration
The Seal of Danzalar is a reference to season 7 of Buffy: The Vampire Slayer, wherein it served as a magical seal seated directly on the Hellmouth beneath Sunnydale High. The phrase "From Beneath you it Devours," appears prominently in "Beneath You" the second episode of the seventh season, in which they are spoken to Buffy in her dreams.