Eel O'Brian is a career criminal and cynical observer of humankind until he is reformed by a friendly monk who takes him in after a botched robbery leaves him wounded and tainted with chemicals from the "Crawford Chemical Works."
Discovering that the chemicals have changed him physically, and the monk's kindness has changed him mentally, he resolves to do the obvious thing: don a costume and fight crime.
Though the grim darkness of typical crime-fighting comics of the early 1940s is evident, Jack Cole's light-hearted handling of the story and artwork makes the tale of Plastic Man unique. Violence is countered by humor, and experimenting with just what a man made of a rubbery body can do makes for a whole library of images that has been mined thoroughly by Marvel Comics (i.e., Mr. Fantastic) and of course DC Comics which currently handles the character (and also "Elongated Man," a kind of second-string Plastic Man).

Vaguely related: Frank Miller and Jim Lee take on Plastic Man from BATMAN AND ROBIN ALL STARS #5, 2007