R'lyeh drowned kingdom

{t}: {u/b}
r'lyeh drowned kingdom enters the battlefield
tapped.when r'lyeh enters the battlefield tapped.
search your deck for a legendary elder-type
creature, exile him face down.at the beginning
of your upkeep put a sealing counter on r'lyeh
.If the number of sealing counters is equal to or
greater than the exiled card's mana cost, remove
the counters and put the exiled creature onto the
battlefield under your control.