Yeah, it does look a little like something from some cartoon show a child would watch, no offense.
Perhaps if it was textured with skin that was rough, perhaps even to the point of being ugly to look at - alien-like in some way, instead of "toon-like" it might have a better chance.
Sorry for being critical, but the first thing that comes to mind when I see it is I can imagine it being on a little kid's T-shirt or something, or backpack for school, so he/she can show off that they watch some cartoon with their favorite character "such-and-such the frog!"
With some work though, like I said it could potentially evolve into something that looks like a hostile alien.
Edit: Perhaps if in addition to a better texture, if it also had more muscle and looked like it could really rip one's head off, and appeared dangerous, that might do it. I suppose you could also add claws, fangs, and such, but as I said in another thread I'd recommend thinking through how it evolved and what type of environment it came from, how it survived, etc.
...But bottom line, you don't want something a child would watch or get a plush doll of to sing and dance with, for this game I'd suggest something that eats children!