The unofficial mascot of the movie: a sinisterly smiling face with screaming mouths for eyes. Granted, it is a horror movie, but the mascot's appearance crosses the line. It doesn't help that they show it every time they advertise for the movie...
In the DVD of Batman Begins upon opening the case, one may find an advertisement for One Missed Call on Blu-Ray that, predictably, had that face staring out at him.
From the movie proper, the undead demon baby holding the cell phone. Oh dear Gord, the undead demon baby holding the cell phone!