Answer: leviathan

AnswerCrossword Clue
LEVIATHANAnything of immense size
LEVIATHANSea monster.
LEVIATHANMONSTER
LEVIATHANGiant
leviathanan (imaginary or real) aquatic animal of enormous size; anything of giant size
leviathananything of immense size and power.
leviathansomething of immense size or power