Judy in Disguise John Fred and his Playboy Band.

Actually, Norman Greenbaum had a followup to Spirit in the Sky called "Canned Ham". Sounded exactly like the first one. Come to think of it, that's also a phenomenon. So many groups who came out with a monster hit, followed with a sound-alike which flopped,ie Procol Harum Whiter Shade of Pale followed by Homberg...."You'd better take off your Homberg, you're overcoat's too long" is a sample line.