But I could change it to:
“Choose to roll instantly an additional defensive dice. If you roll a black shield the Cape is destroyed. You lose the next turn.”
This is more like a saver from dying (if you don’t use the NA rule of healing potions). If you give a cost of 200gp, I think it will work fine and make your players to consume some of their gold, but the Wizard will use it only if he is dying and failed to defend the attack...
"come on guys! I am tanking!"\ 
