If the Watchmen movie didn't burn you out on the idea of cosplaying in that world, your gear options just got a whole lot better with a variety of inkblot masks that change pattern.
It's not quite as cool as the comic version, which had liquid caught between two layers, or the movie version, in which the ink appeared to be re-pooling. The mechanism appears to be a heat-sensitive ink around the mouth area that darkens with the warmth of your breath and opening and closing of the mouth.
Video of it in action after the jump. Hey, it's better than a lenticular solution, which is what I was expecting.
Via Fashionably Geek