Did this creature based on the concept of Creature Box:
Creature Box concept
Used Zbrush, Keyshot, Photoshop and Lightroom.
Rendering was done using one of my HDRI from a bundle that you can find on my gumroad:
HDRI bundle
Any feedback is welcome 
Nicely done man, really love the environment and the texture of the character!
that’s awesome" I would love to see a timelapse of your progress. do you usually record your process?
Really cool! Haha, he solidifies my fear of deep sea waters, 
Nicely done! What methods did you use to get the rock and background to fit in so well with the character? As in making it look like they actually go together? I’ve tried compositing like that but have always had lots of difficulty with it. Any tips/settings you use would be appreciated!
Hey guys,
Unfortunatly I did not record my process.
For the integration of the rock and background I used a 120mm lens inside keyshot with a f-stop set at 0,3.
Also I did light the scene with on of my HDRI that you can find on my gumroad here:
https://gumroad.com/arnaudlonys
Other than that I just added a vignette, some grain and chromatic aberration.
Hope it helps
Nice one Arlo!