Heartborn

Before play begins, reveal your library and exile
all Heartborn cards. Shuffle it afterwards. If a creature you control prevents damage you may
discard a card to put a Heartborn card into play attached to that creature.
Enchanted creature gets a Link counter when it prevents damage, and has "Protection from cards
with a converted mana cost less than or equal to
the number of Link counters on it." Remove the counters if Heartborn leaves play.