Aplysia dactylomela, a genus of sea hares, in a mating chain

(Image Credit: Anne DuPont)

Sea hares, like all sea slugs (see flatworm above), are hermaphrodites. But that’s not all - they’re efficient hermaphorodites! When sea hares mate, they form a mating chain of several animals!

The sea hare in front acts as the female to the one directly behind it. Sometimes, they even form a giant circle, with everyone inside happily mating the day away. (Source)