Here is a concept that I did for a weekly topic on the Hybrid Collective blog.
I started this guy with only the intention that I wanted him to have heroic proportions. Sometimes I like to work without many intentions regarding the design and the final product. This way It does not put pressure on the design you and you can really experiment and surprise yourself.
A few days before I painted this I had watched an episode of River Monsters about sting rays and sharks. This can be clearly seen in the spike appendages on the back and the shape of the head. I also see some influences from Avatar and District 9, almost a mish-mash of the two.