Was using Qah rune to heal for the amount Ward negates if you successfully resist a spell. Instead of healing it showed as negative heal (- green number) and killed my creature.
Here was the weird sequence of events (to the best of my memory):
My Crypt had Shell on and was being attacked by an enemy, this consumed the shell, then proc’d Arcane Enchantment on my Phase Knight (he already had ward on him) as a result on a “on hit” Night Sword attack on him. The ward resisted this, but then “healbombed” me for a negative green amount, killing my Phase Knight.