Tutu: Cut ribbon long enough to tie around your child's waist. Cut 30 4' lengths of tulle and knot each piece around ribbon. Cut jagged edges into ends of tulle. Cut a zigzag edge on a 3"x 15" strip of peach felt; hot-glue to front of tutu waistband.
Monster Scarf: Cut a 14"x 45" length of tulle and fold it vertically to resemble a scarf. Download the templates for the face at parents.com/girly-ghoul. Cut out and hot-glue white felt eyes and teeth plus black-felt pupils and nostrils to one end of tulle. Cut out and hot-glue 33"-long zigzag-edged strip of felt to center of scarf. Drape monster face over one shoulder, wrap it behind your child's neck, and tuck tail end of scarf under tutu on opposite side.
Mask: Enlarge eye openings of mask to improve child's field of vision. Cut felt to cover mask, and glue felt to mask. Cut eight triangular shapes of tulle. Layer two sets of four triangles to create ears and hot-glue to headband.