I have seen this guy only twice.
good or bad guy? it retracts into itself when disturbed, it does not pull into the rock.
and this guy ... he gets around a bit. Generally looks like a clear tube, but every now and then it looks like the picture with brown bits sticking out. Seems to come out more at night.
Hope the pics are okay. I'm just new to this, and still getting the hand of things. Thanks!!