Curse to Counteract Healing Spells

"I have bound it to the left hand path. The force of any healing magic will be reversed, and magnified tenfold."

- Morgana to Agravaine

The Curse to Counteract Healing Spells is an enchantment that not only reverses the effects of healing spells, but magnifies them tenfold.

History
When she learned that Arthur intended to use magic to save Uther's life, Morgana cast this enchantment on a charm by placing it in her fireplace and chanting a spell that bound it to the left hand path. The flames rose higher and engulfed the charm, yet when Morgana removed it from the fireplace it was cold to the touch.

Agravaine then took the pendant and placed it around Uther's neck. When Merlin (disguised as Dragoon) later tried to heal the king, the spell backfired and resulted in his death, leading Arthur to believe that he had killed him on purpose (The Wicked Day).

Trivia

 * The spell used by Morgana to enchant her pendant translates to silver thread, rush to the left hand path; rush to evil; rush against every good skill (The Wicked Day).