The proud history of science fiction publishing offers a near-limitless supply of WTF book covers, it seems. Flickr user Zimpenfish just uploaded some real masterpieces of dementia, including one that might be NSFW.

Check out more incredibly pulpy, inexplicable covers over at Zimpenfish's Flickr stream. Here are the ones that baffled us the most. Please tell us what you think is going on in these covers! And remember, the final one is possibly NSFW (and will bruise your retinas.)

Another round of SF book covers to make you ask, "What were they thinking?"

Where Do We Go From Here? Noplace but down, probably.

Another round of SF book covers to make you ask, "What were they thinking?"

That price sticker seems strategically placed to try and make her outfit look classier.

Another round of SF book covers to make you ask, "What were they thinking?"

I think that loincloth is what you wear when you want to draw the attention of... the Manhounds!

Another round of SF book covers to make you ask, "What were they thinking?"

What is that guy doing with his shirt? Is he feeling hot and stuffy because of the vapors coming from the lizard-elephant?

Another round of SF book covers to make you ask, "What were they thinking?"

What on Earth do you think that creature is? I've been staring at it for ten minutes and I still have no clue. I wonder if the book designer found its mummified corpse in the woods and brought it home. Update: According to commenter William, it's a Jenny Haniver.

Another round of SF book covers to make you ask, "What were they thinking?"

Ah, Stan Lee. I like that the one guy's head is perfectly square. And the tiny guy is climbing up to scratch the square-headed guy's nose for him.

Another round of SF book covers to make you ask, "What were they thinking?"

That's not a happy looking centaur. That's a centaur with scoliosis or spinal biffida or something. Seriously, I thought one of the perks of being a centaur is you don't have to try and have an 18-inch waistline.