Yeh'kinya's Scroll

Yeh'kinyas was used instead of the Egg of Hakkar to summon the Avatar of Hakkar in the Sanctum of the Fallen God of the Sunken Temple if the quest had already been completed. Unlike the Egg of Hakkar it was not consumed after use.

Source
This item could be obtained by speaking to Yeh'kinya after completing the quest The God Hakkar.