Library of Atlantis

Comes into play tapped. When library of Atlantis
comes into play sacrifice an island or bury
this land.
{t}: Add {u} to your mana pool.
{x}{t}: Look at the top X cards of your library and
if there is a merfolk creature with the converted
mana cost of X or less, reveal it and put it in your
hand. Reshuffle your deck afterwards.
{u}{u}{u}{t}: Untap target merfolk creature it gains hexproof.