I just made these for my son's preschool class tomorrow and they turned out pretty cute! Just made them up, so there's not an official recipe.
White Dipping Chocolate (or bark coating)
Melt the chocolate until smooth and creamy. Dip Oreos in chocolate until completely coated. Remove and place on wax paper to cool and harden. Before they harden completely, add a face with sprinkles. I used bat shaped sprinkles for the eyes and then regular chocolate sprinkles for teeth.