I discovered this scan while looking for completely unrelated stuff. If I remember correctly, I did the drawing for a commission that never came through in the end. It was supposed to be the Dungeons & Dragons monster tarrasque (which is different from the mythical tarasque) but I didn't have the best materials to work with. I'd never seen a Monster Manual in my life, so I had to base it on a vague description and a low-res image that looked mostly like a pissed off demon with a reptilian tail.
Now that I google tarrasque, I can see the official D&D Tarrasque looks very little like my version, apart from the obvious stuff like horns and the armored reptilian nature of the beast. In fact mine looks more like something that should be wrestling Godzilla or teaming up with him to defeat a three-headed dragon. I have no idea where I got the shoulder spikes from. (Dino Riders Kentrosaurus maybe?