The female Sacculina parasite will infect the genitals of a male or female crab. It looks like a barnacle at first, but then it’s soft body enters inside the crab and it’s shell falls off. The soft body will penetrate every part of the crab, it’s arms, legs, even it’s brain, until it re-emerges at the crab’s genital area, and then replaces the crab’s reproductive organs with it’s own, regardless of the crab’s original gender. The parasite also disables the crab’s ability to molt it’s shell or regrow lost limbs, as this could interfere with the parasite. So, the female Sacculina waits for a male Sacculina to impregnate it, and then it forces the crab, regardless of it’s actual gender, to revert to female crab pregnancy instincts and care for the parasite offspring as if they were it’s own.
(via bradofarrell)
