This one showed up for a short time one day, I was fortunate enough to get a pretty good look at it.
My creatures book lists two species in two genera this could be (Anilocra spp. or Renocila spp.) but I'm not sure how or if it's even possible to distinguish between them. I've also just found out that apparently they are not parasitic or harmful to their hosts!
Seen ~ 1800’ deep within submersible. Location and exact time is not exact.