oh yes, I fully agree with Manu. There's no caustics occurring. I knew something was bugging me about this. Nice job so far. Love the closest, detailed-out tentacle, but shouldn't it be a little thicker to convey more accurate diminishing perspective? That next closest one has such different lighting, it seems far away, yet their thicknesses are so similar. That's the trouble with detailing one part of a rough image so much in the prelim phase, you run the danger of needing to back-track and change it. Of course, don't do anything that would jeopardize the feasibility of completing this image.