When this Case enters the battlefield, destroy up to one target creature that was dealt damage this turn.
To solve — Three or more creature cards were put into graveyards from anywhere this turn.
(If unsolved, solve at the beginning of your end step.)
Solved — This Case is a 4/4 Gorgon creature with
deathtouch (Any amount of damage this deals to a creature is enough to destroy it.) and
lifelink (Damage dealt by the creature also causes its controller to gain that much life.) in addition to its other types.