Ariel, Soul of the Sea

At the beginning of combat on your turn,
each Merfolk creature you control explores.
(its controller reveals the top card of their library.
If it's a land card, they'll put it into their hand. Otherwise, they'll
put a +1/+1 counter on that creature, then choose
to either leave that card on top of their library or
put it into their graveyard.). Whenever Ariel, Spirit
of the Sea attacks, you may put a land card from
your hand onto the battlefield. If you don't
draw a card.