No, the answer is not Steely Dan, but the steely Slinky toy! Invented by an Naval engineer (by accident) at a Philly shipyard in 1943, it has become an icon over the years. Originally sold for a buck, it now goes for $5.95 or so on The inventor sold 100 million of the things in the first two years after he finally got toy stores to carry them. Here’s a Popular Science article from 1945:

A Slinky consists of 98 coils of high-grade Swedish spring steel and is 2-1/2 inches high. In Viet Nam, the Army used them as emergency antennas for their short-wave radios. They are the official state toy of Pennsylvania, and they are alluded to in a lot of books and movies. My favorite reference, of course, is this one from the second Ghostbusters movie, where Egon describes his strange childhood:

Dr. Ray Stantz: “You mean you never even had a Slinky?
Dr. Egon Spengler: “We had part of a Slinky. But I straightened it.”

NASA has had fun fiddling with Slinkys in space, where they have strange properties unknown to us on this planet. Because a high-frequency sound wave travels faster than a low-frequency one, a Slinky makes a cool swooshy/boingy sound if you hold it vertically and hit the bottom end with a drumstick; the sound is so unusual that avant-garde composer John Cage used it in a 1959 symphony called Sounds of Venice. And I’ve heard a foley artist used a Slinky to make that laser-blaster sound in Star Wars.

Here’s an ad for the Slinky from a 1953 Abbott and Costello comic book; it appears to have been drawn by the artist who did the Dubble-Bubble chewing-gum ads: