The U.S. Postal Service will celebrate Message Monsters with the most playful, customizable Forever stamp design ever. 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.

Art director Antonio Alcalá designed the pane with original artwork by Elise Gravel, author and illustrator of popular children’s books.

The first-day-of-issue event for the Message Monsters Forever stamp is free and open to the public. News of the stamp is being shared with the hashtag#MessageMonstersStamps.