Hourglass of Eternity

This item provides information about a time storm around the Bronze Dragonshrine in Dragonblight.

Source
This item is provided for two separate quests:

In the first quest, you place the Hourglass and the Infinite dragonflight assault you (and the hourglass), only to be repulsed by you ... and a future version of yourself.

In the second quest, you return to the bronze dragonshrine with the hourglass, place it, and help defend your "past self" against the infinite dragonflight.