In Batman Returns (great Christmas movie, by the way), the Penguin's initial scheme is to gain access to Gotham City's birth records. He intends to record the names of all of Gothams' first-born, and then kill them. The means of murder is a mass of penguins, armed with missles.
This was a great idea, too. Only, next time, I think the Penguin needs a better radio control system. Okay, so maybe it wasn't a great idea. Maybe Penguin would have been better off just firing the missiles from a central location and not worrying about flightless waterfowl.
What you see below are concept art drawings for the penguin-missiles, followed by what they actually created.