The Crushed Eye Orb is located in a chest in the Undead Crypt. The chest is located within the room directly after meeting Agdayne. By the bridge with the two Syan Knights there is a ladder. To reach the ladder the player must jump off of the ledge to the lower platform.To the left of the door is easiest. There will be the bottom of the ladder and then climb it to get to the chest.
The Crushed Eye Orb is used to invade the world of the traitor Licia of Lindeldt. In order to do so, the player must go to Licia by the contraption which requires the Rotunda Lockstone in between Majula, Heide's Tower of Flame and Huntsman's Copse. Once there, a message telling the player that the Crushed Eye Orb is shivering will pop up, and the player will be allowed to invade the world of Licia of Lindeldt using the Crushed Eye Orb.