Mostly made famous by Ernie's song on Sesame Street (see below), this rubber ducky, or as Ernie calls him, "Rubber Duckie," was created by Alan Jay Clarolyte in 1954 (per an advertisement a friend posted on farcebook).
These are photos of the one I have in my collection. There are cleaner ones out in the world, without scratches; but, I got what I could find! And, I love him.