Thanks to your low-light vision, you can see a beetle swarm coming towards you. They are leaving a slick yellow trail of acid in their wake. Also, there is something else down there with the beetles, climbing the walls towards you. It appears to be nothing more than a central eye, with 6 sharp legs sprouting out around it. It is avoiding the swarm, but still coming towards you.
{OOC: The monsters are down inside the hole still, about 30 ft down, or so.