Director Ridley Scott brought us the chest-bursting Alien in his 1979 movie by the same name. The director is now back on the big screen with "Prometheus," a film set in the "Alien" universe that opens June 8. Will the aliens of "Prometheus" rival the original Alien in pure parasitic glory? We're not sure, but nothing gets the science fiction horror genre going like alien parasites.
While Scott's Alien is mostly into gore, other parasitic alien creatures are more subtle. Stargate's Goa'uld symbiotes wrap around their hosts' brainstem, controlling their behaviors. Star Trek's Ceti eel takes a similar tact, entering the brain through the host's ear for maximum ickiness. However it happens, parasitic infestation rarely ends well for the host.
Fortunately, real-life parasite loads are at an all-time low in human history, thanks to modern medicine. Unfortunately, plenty of the fictional parasites that have gained fame on film have parallels in real-world ecology. Certain types of fungi can control the minds of ants, for example, manipulating the insects into carrying the fungus to an ideal place to grow — and then using the host as fertilizer. The mammalian parasite T. gondii may be linked to human mental health. And parasitoid wasps, which lay their eggs inside other living insects and invertebrates, were the direct inspiration for the chest-bursting scene in "Alien."