Ocean Master,Leviathan's Bane

Islandwalk
Whenever Ocean Master attacks, reveal the
top five cards of your library. You may put up
to one Leviathan, Kraken, Octopus, Whale or Serpent creature from among them onto the battlefield tapped and attacking. Put the rest
on the bottom in a random order.
{1}{g/u}: Sacrifice target Leviathan, scry 2.