Devouring Serpent

You conjure a large serpent's head that splays open, waiting for its next meal. A 20-foot-radius serpent mouth appears, centered on a point within range and lasting for the duration. The serpent's fangs visibly drip a hissing poison and its eyes wildly search the battlefield. No light, magical or otherwise, can illuminate the inside of the serpent's maw, and creatures fully within the area are blinded.

The head has pushed through the earth and the area is considered difficult terrain. Any creature that starts its turn in the area takes 2d6 poison damage. Any creature that ends its turn in the area must succeed on a Dexterity saving throw or take 2d6 acid damage as the mouth shuts down on it, causing the creature to fall prone.