This creature is known as a Zelroque. Found in the central volcanic regions of your imagination, this creature catches its prey by hiding in the magma in lava flows, pouncing on their unsuspecting victims and dragging them into the lava just long enough to kill them and seal them in a thick coat of lava, preserving them in a form fitting air tight stone casket until they decide to feed. They only eat every 3 months but the entire time in between feedings they're constantly storing food. They only go after humans if there are slim pickings in the area it resides. Otherwise they'd rather strike up a conversation about the weather or something (which is always constant, being a volcanic atmosphere).
This took me just over 2 hours. As always, don't be afraid to leave any constructive criticism!