12 Unnecessarily Nightmarish Creatures That Scuttled Straight Out Of Hell

Who'd have thought that a barnacle could be such a nasty piece of work? It's just a barnacle after all.

Well, the Sacculina carcini does its level best to win the "most repulsive parasite in the ocean" prize (for which the competition is fierce), by not only freeloading off hard-working marine animals, but also being a total dick about it.

The female will colonise the underside of a crab, latching onto the place where a female will usually keep her eggs, sending root-like tendrils into the body of the crab to begin sucking all the nutrients out of it as she lays her eggs.

A male will then come along and fertilise batch after batch of eggs by implanting himself into the already implanted female like the hideous barnacle version of a Russian Doll.

The pair will take over the body of the crab, stopping it from shedding its shell (which would dislodge them) and altering its behaviour so that the crab will actually begin caring for the barnacle's eggs as though they were its own.

If the bastardly barnacle accidentally latches onto a male crab, it doesn't simply go "oops, wrong number" and swim off to ruin someone else's life. Nope, the barnacle makes the best of a bad job and forces the crab to change sex. It does this by sterilising it, flattening its abdomen and forcing it to release female hormones so that it will care for the eggs and even perform female mating dances.

Talk about adding insult to injury.