When I saw these originally (I can’t remember where, sorry!) the person stuck a lollipop stick in the oreo and dipped the cookie in white chocolate, then placed the cookie on waxed paper before decorating while the white chocolate was still wet.
We have Oreo candy molds (can be purchased here for $1.99) that let us cover a cookie in chocolate. So we melted white almond bark and covered the oreo in that. When the bark was set, we popped the cookies out of the mold and heated up one more square of white almond bark. The kids put dots of the melted almond bark on their white oreos so they could use it like glue to attach the candy corn nose and mini m&m eyes and smile.
Even easier? Buy the white chocolate covered oreos so all you have to do is all the face!
(The boys were happier than they look, I promise. They just weren’t thrilled about smiling for mom’s camera when they were anxious to dig into their oreo creations!)