I took a fresher down there yesterday for their FIRST underground experience EVER and I promised it wouldn't be scary at all. They saw the snakeskin, panicked, and we had to leave very quickly for the pub. poor lad. I too was very freaked but heck, I got some shots for everyone to see and it ranks in my top 5 weird experiences underground.
It's 15 minutes in, can't miss it. You walk around a corner and think 'Wat is that thing?'. Photos attached.