Being the sick juvenile fuck I am, I seem to frequently choose somewhat sexually-related organisms to talk about. This time I thought that merely talking about animals that are typically shaped like penises, the sea cucumbers (Holothuroidea), wasn’t nearly pornographic enough, and so I present you the fish genus Carapus in the Carapidae family (pearlfishes). These little, slender fishes are well known as commensalists (they gain advantage of their host, but do not harm it or help it in any way) of sea cucumbers, because their shape allows them to penetrate the echinoderm’s anus and live in their rectum. Which is kind of unexpected, but hey – if you were a big bad predator, would your look for dinner inside the ass of a sea cucumber? I don’t think so. Another genus of Carapidae, the Encheliophis, not only lives in the same bizzarre place, but also parasitizes the sea cucumbers by eathing their gonads. What pricks.