No bones about it, partygoers will get a scream out of this playful treat.
Cut the marshmallows in half widthwise using kitchen shears dipped in confectioners' sugar (this keeps them from sticking).

Carefully pull each cupcake liner partially away from the cake and tuck half a marshmallow between the paper and the cupcake to create the skull's jaw.
Frost each cupcake and marshmallow, then add Junior Mints with white frosting dots for eyes, a chocolate chip nose, and slivered almond teeth.