Martian swamp creature from Fifteen Hundred Miles an Hour (1895) by Charles Dixon. Modeled in ZBrush, composition and glow effects added in Photoshop.
I was working off a pretty detailed description, so I was somewhat constrained design-wise. If I had had my druthers, I would have made the head smaller. Might look less goofy that way. I added extra limbs, since my Martian creature designs tend to be influenced by Burroughs' vision of the planet.