In the fifties cars had fins and lots of chrome. MAD parodied that to the Marine Corps Hymn.

From the gaudy grills of Cadillac to the fins of Chevrolet,
We will push GM's new models and make obsolescence pay.
So to heck with Ford and Chrysler, boys,
And to sports cars from afar,
We won't stop 'til every family owns a brand new GM car!