Nautilus, Deepfathom Titan

As long as there are 40 or more cards in your graveyard Nautilus assigns combat damage with its toughness instead of its power.

Whenever you cast a Leviathan, Serpent, Kraken, or a Octopus spell, you may put the top three cards of your library into your graveyard.

Once per turn you may cast a Leviathan, Serpent, Kraken,
or Octopus spell from your graveyard, you may also play lands from your graveyard.