The natural world is home to more than 300 species of anglerfish, each uglier than the last, but we're mainly interested in some of the 160 species that lurk in the inhospitable depths of the world's oceans [source: BBC]. Between their upturned, gaping maws, needle-like teeth and distensible bellies, which stretch to digest prey twice their size, you wonder how they manage to feed at all. The answer lies in clever camouflage and a sinister trick of physiology: an evolved spine that juts out like a lantern and acts as phosphorescent bait, luring other fish to their doom. And if that isn't sinister enough, some species also sport spaghetti-like hipster beards [source: Pietsch].
Not monstrous enough for you? Wait until we delve into their nightmarish mating practices. In 25 species, once the comparatively tiny male anglerfish gives his mate-to-be a love nibble, his body physically fuses to hers. As he is absorbed, he loses his eyes and fins, unites his circulatory plumping with hers, and spends the rest of his life as a, pardon our French, sperm factory [source: Pietsch]. But hey, life is pretty hard in the freezing ocean depths, where pressures tilt toward the crushing, sunlight is nowhere to be seen and meals on the fin are both scarce and elusive [source: Pietsch].