17 prank envelopes - witty pranks for adults funny envelope for birthday & holiday card. practical jokes by mail prank for friends & family, or coworkers gag, inappropriate office pranks for adults better me now you can send pranks by mail! this pack of 17 funny gift prank envelopes allows you to humiliate or surprise your family and friends. some designs are embarrassing and will be seen by the mailman and whoever the receiver lives with. some are shocking and may cause them to think they are late for payments or deadlines. each one is a funny gag you can have fun with!