Set aside 12 candy melt discs. Follow the directions on the candy melts package to melt the remaining discs.
Dunk each OREO cookie into the melted candy, completely covering it. Use two forks to lift it out, tap off the excess and transfer to a waxed paper-covered baking sheet.
Press one of the extra candy melts onto the face as a muzzle and add an M&M nose, candy eyes and marshmallow or M&M ears. Let sit until candy firms up.