I used the same skull for a Monday Morning Mystery twice, but the second (this past Monday), I put a fake over-sized quarter that I bought on the Internet next to it just to throw your perception off.
Below are pix of the skull with a regular (inch-diameter) quarter and the fake three-inch-wide quarter (I think it's a paperweight), and one of all three together.
The photos are all the same photo, cropped differently. It was presented less than ideally, but so it goes. A few folks were on the right track, so kudos to them.
(By the way, Pat Price thinks the skull is an Opossum's... It is tough to tell without any teeth in the skull... Sorry about that.)