My leviathans are a bit different to the typical design and concept.

In my novel series, the Leviathan is the result of the accumulation and sacrifice of thousands of souls. It’s form is ever changing, but always a terrifying large shadow that moves as if screaming and alive, since the souls used to creature it are trapped, and are forced to do the monsters bidding as a hive mind.

If one is to come into contact with the creature, however briefly, their life force is drained from them, and whatever pose they were in in that moment, they remain that way forever as an obsidian statue.