Pop Dongle is a mobile phone attachment that emits the sweet-and-salty smell of popcorn as you play the brand’s mobile game, Poptopia, available for iPhone and iPod Touch. Every time you swipe the butter inside the game, which asks players to pop corn kernels, the Dongle will emit a spritz of popcorn scent. How did they do it? The dongle plugs into the audio jack, so the game emits a certain frequency signaling it to go ahead and spread the smell.