I would like to suggest a creature that hides in the shadows and is only aggroed when you retreat from the dark depths (ranged). Just when you think everything is okay and it’s getting a little easier to see, you breath a sigh of relief. For good measure you turn around, just to make sure, but there it is, a beast with a mouth full of teeth. Grabbing and crushing your tadpole with it’s powerful jaws >.< and just like the Leviathan, leaves you in the water with it. A squishy little treat.