Barricades are at the ready. Something's coming down in PPG Plaza. And that "something" is a large plastic Slinky. Mike Hennessy of Carnegie Science Center says it has something to do with elephants.

Modern-day variations include the plastic Slinky, the giant Slinky and the Sound FX Slinky, which makes sounds as it "walks." There's also a light-up Slinky, and, for the Slinky collector ...