Ah, the brownies. The question everyone wants answered! Sass did use a Christmas tree cookie cutter, but I didn't notice that at first.
The first thing that came to mind for me was Edvard Munch's The Scream. I think that's because of the way I approached it though. I saw it from the side at first, and it was a bit distorted with the parchment paper underneath. It's not nearly as obvious when looking straight at it.
My second thought was immediately Herman Munster from The Munsters, quickly followed by Frankenstein. (Tina, you got that one spot on!)
Who knew that my Sass could be so talented with just a Christmas tree cookie cutter? :)