Kraul, Demon of the depths

Hexproof, Defender
{t} tap all creatures that entered the battlefield
this turn.
{x} Sacrifice X islands and X Merfolk, Krakens, Leviathans, Octopi, Sharks, Blue elementals, or Serpents: Kraul, Demon of the depths looses
defender and gets +XXXX/+0 and islandwalk
until end of turn.