Flavorwire has an amusing bit on the worst covers for classic works of literature ever. Some were very droll, like the Brazilan cover of The Shining which looked like it had been lifted from a 1980s hair care advert (blonde woman, power hair, shoulder pads, absolutely nothing about psychic kids or haunted htoels or nothing). Some were just doomed by the poor typology and design aesthetics of the 1970s, the Time that Taste Forgot.
My personal personal fave for balls to wall inappropriate craziness however was this Wizard of Oz cover, fetchingly reimagined as a Clancyesque technothriller.
I particularly like it because there's no language gap to explain how the cover artist got it so horribly wrong. The Shining at least had a sort of thematic link to hair care through the, er, shiny thing. Which hair care ads value very highly.
Normally publishers will send you copies of the art work to approve before printing, and normally unless you're a dick you'll just let any small, inexplicable quirkiness (like the bizarro helicopter on the US cover of Final Impact) go through to the keeper, unless it's completely out of hand.
Like the cover of Felafel in Italy.
I dont recall ever seeing prerelease artwork for this, and Im sort of glad I didn't. It's now one of my favorite covers, and I cherish the two remaining copies in my possession. What is that car. Why is it parked on an alien beach planet. Is the felafel guy in the boot.
None of these questions were ever answered. But that's cool. Because none of my royalties ever turned up either. Despite the book being a best seller there.