Phyrexian Metamorph and Mother of Runes
I copied my opponents Mother of Runes with my Phyrexian Metamorph. A turn or two after it entered my opponent attacked with their Thragtusk and I blocked with my Mother of Runes.
Before damage I activated the Mother of Runes and gave it protection from Green. However, even with this protection from Green; the Mother of Runes still died. There were no other added effects or abilities that would cause it.