Thats hilarious and soooooooo freakin true. I stepped up to a 125 years ago and now Im dying to go 250 or bigger...
You are right that does look like a dinosaur head... You could easily find more driftwood that looks like bones (cut up the other one you have too) and make a half out of the ground skeleton... That would be insane. All with drift wood then cover it in moss... If you found the right picture of a half buried skeleton it would be pretty simple...
But you may not want a theme type tank!
Regardless, it totally does look like a head!
Actually, I rather like themed tanks. Yours is one of my absolute all-time favorites! I'm seriously fighting the urge to turn one of my other tanks (either a 40B or a 55) into a Hobbit home/hillside. Definitely not for everyone, but I've never tired of the trilogy since I first read them in the 70s! lol
I like to make 3D backgrounds and since I did my first two I've learned a great deal. I think on my next one I'm going to carve a subtle fossil into the faux rock...I have real rocks form the local creeks full of shell fossils - I'd add a one or two in the hardscape to tie it together.