Fishermen off the coast of the Netherlands pulled in a very surprising catch. Conjoined twin harbor porpoises were wrapped up in their nets. Hard to know if we should refer to the creature as singular or plural, but either way, it's only the 10th of it's kind recorded, according to the New Scientist:
Cetaceans are a group of animals that includes whales and dolphins, and it's rare for them to have regular twins, as the mother's womb is generally not big enough. There's no way of knowing how frequently two-headed babies are born, since the ocean is deep and guards its secrets, but scientists believe it's very rare.
You know what's not rare? This joke: