Ouroboruo Defense

While this card is in play and you have a
Monk Creature active;
• When your opponent activates an ability
or effect that costs {x} Mana, you can target
one of your Monks; pay {x}+1. That Monk
loses 20% of its maximum HP. Negate the
ability or effect. This artifact can only
negate abilities or effects that would cause
damage.