Ishloch, the Tempest's Doom

Ishloch, the Tempest's Doom can't be countered.
Hexproof from nonlegendary spells
Whenever Ishloch, the Tempest's Doom or
another Kraken, Leviathan, Octopus, or Serpent
enters the battlefield under your control, return
all artifacts and creatures to their owners' hands
except for Krakens, Leviathans, Octopuses, and Serpents.