Board Thread:Rewatching "Merlin" - Season Four/@comment-5102537-20131116154357/@comment-5674726-20140201155841

That pendant was potentially an amazing weapon for Morgana that is, alas, never used again.

There is no way that the spell to enchant the pendant was devised to counter healing magic. The odds of somebody being in a position where they would use such a thing are ridiculously slim, so much so that nobody would go to the trouble of creating the spell if that was its only purpose. It only makes sense if it was meant to be used to reverse and amplify the effects of magic used on the wearer as it would then be quite an effective shield against offensive magic.

Imagine if Morgana was wearing it when Merlin tried to strip her of her powers.