I modeled this slightly-toony skull for an assignment, and was pleasantly surprised by it as I worked on it. I hope you enjoy, as I had a lot of fun working on this!
The skull was modeled in Autodesk Maya. Hard to believe this guy started off as a default cube, but look at him now... all smooth and high-poly. While he does resemble a photo-realistic skull, he's meant to invoke a slightly cartoony and exaggerated feel; note his single tooth that spans across his entire jaw. That being said, there are subtle details modeled into his surface, such as his jutting cheek bones, the curve of his nasal region into his jaws, and the subtle divot around his parietals.