This is another clay character, he was created anatomically disproportional on purpose. Yes, I have to improve on my hand modelling skills as well. 
:Z :o 
P.S. I fixed the hands.
He looks good. Have you considered making him a cave? Paper mache would work well. ( i prefer wallpaper starch to flour paste for that btw ) Also, a good way to make a dirt floor: mix sand and dirt with concentrated gelatin. You can kind of sculpt it, and when it dries, it’s hard as a rock.
I tell ya, you must be psychic, I was discussing that with my buddy yesterday. He has a remote control robot we planned to use. We were going to wrap it in tin foil to avoid copyright issues and call him Boxor from planet bauxite. This robot would have an encounter with this really dumb character from the stone ages. Part of that involved making a prehistoric set like you mentioned. Thanks, again for your suggestions, knowledge and know how, your thoughts are always valued and appreciated. 
If you are going to be making scenery, here’s a good way to make a tree:
- bend up some wire, and use masking tape or hot glue to put it together into the shape of a tree
- Roll/crumple some bits of newspaper into blob/worm shapes, and tape them onto the wire frame to fill it out. Leave some bare ends on the wire
- paper mache the outside, and use bits of other stuff, like fabric/tissue, whatever, to give it texture
- Take a chunk of foam rubber, and start ripping pieces off of it, while it is somewhat compressed, with needlnose pliers, until it is the shape of a piece of your tree top
- Cover it completely with dark green house paint. (you may want to do this by squishing it around in a shallow pan. trying to paint foam with a brush is next to impossible.)
- while it’s still wet, cover the outside of it by sprinkling it with light green confetti
- after it dries, stick it onto the wire trunk. ta-daaaa.
Cool, thanks.