Crefton Fathom is a location in Torment: Tides of Numenera.
Tol Maguur is trapped here, release her from the illusion will give you some XP. Interact with the snake statue will tell you the true nature of Dracogen, and if you touch it, you will get hurt but also get the Recalescent Stone. (Best Ornament item)
Ask What is the answer, and the Philethis will award you some XP.