You know how magazines are always telling you to make the most of your small apartment by maximizing the vertical space? That's sort of how Beatnix operates. Located inside a narrow storefront on the corner of Washington and 12th Street, this Miami Beach costume shop is packed floor-to-ceiling with a myriad of wacky accessories, from top hats to tutus. Most packaged costumes run $50 to $60, while smaller accessories are sold à la carte. Feel like letting it all hang out with some nipple tassels ($16) and gold booty shorts ($30)? Beatnix has 'em. Prefer to cover your face with a rubber gas mask? That's here too, for just 15 bucks. The staff is friendly without hovering, and Thursday through Sunday, the store is open until midnight, meaning you can grab something last-minute for that festival or costume party and still look like the baddest one there.