The four monster illustrations on this pane of 20 stamps invite interactivity with dozens of self-adhesive accessories on the selvage. The monster-ific accoutrements include cartoony voice balloons and thought bubbles with exclamations and salutations, hats and crowns, hearts, stars, crazy daisies and other fun flair. The characters populating the pane include a roundish, rosy rascal with a sunny tummy; a silly, striped imp waving a four-armed howdy; a squiggly, squid-like yellow critter with enough eyes to go around; and a reddish rapscallion in short shorts. Whimsical, wacky and inviting inventiveness, these creatures are sure to charm everyone along their mail delivery journey.