Morgana's Enchanted Pendant

"The force of any healing magic will be reversed and magnified tenfold. By trying to cure his father, Arthur will seal his fate."

- Morgana to Agravaine

Morgana's Enchanted Pendant is a piece of jewelry owned by Morgana Pendragon. She enchanted it to reverse the effects of healing spells.

History
When Agravaine informed Morgana that Arthur intended to use magic to heal Uther, she cast an enchantment on the pendant that would cause it to reverse the effects of healing spells.

Agravaine took the pendant and placed it around Uther's neck. When Merlin (disguised as Dragoon) later tried to heal the king, the pendant reversed the spell and killed him instead, leading Arthur to believe that he'd killed his father on purpose.

Gaius later found the pendant around Uther's neck. He showed it Merlin to prove that Morgana was likely behind his failure to heal the king (The Wicked Day).

Trivia

 * It is possible that the pendant is an artifact of the Old Religion, as it bears the emblem of the Triple Goddess (The Wicked Day).