In advance: Make zombie cookies. Prepare and roll out dough. Using mini cutters, cut 1 tombstone for each treat. Bake and cool cookies. Place cookies on cooling grid over cookie sheet; cover with thinned color flow (Link to technique on p. 128). Place cookies on waxed paper-covered board. Let dry.
Using full-strength color flow and tip 8, pipe pull-out arms. Attach eyeballs. Pipe in tip 2 mouth (pat smooth with finger dipped in cornstarch). Pipe tip 2 tooth. Let dry overnight.
Bake and cool cupcakes. Ice smooth in buttercream. Insert zombie.