And you thought Jon and Kate had it rough...

Through the miracle that is Wikipedia, I bring you one of the strangest stories I've ever read about reproduction in the animal kingdom: The Deep Sea Angler. It's common knowledge that the females of many species (spiders for example) are much larger than their male counterparts, and in some cases following fertilization the male either dies or is eaten by the female (e.g., praying mantis). This is the first instance I've ever heard of in which the male is merged with the female:

At birth, male ceratioids are already equipped with extremely well developed olfactory organs that detect scents in the water. When it is mature, the male's digestive system degenerates, making him incapable of feeding independently, which necessitates his quickly finding a female anglerfish to prevent his death. The sensitive olfactory organs help the male to detect the pheromones that signal the proximity of a female anglerfish. When he finds a female, he bites into her skin, and releases an enzyme that digests the skin of his mouth and her body, fusing the pair down to the blood-vessel level. The male then atrophies into nothing more than a pair of gonads, which releases sperm in response to hormones in the female's bloodstream indicating egg release. This extreme sexual dimorphism ensures that, when the female is ready to spawn, she has a mate immediately available.

Gives a whole new meaning to the term "joined at the hip".