In the Ridley Scott film, an interplanetary space crew encounters a nest of alien eggs, from which the parasitic Xenomorphs explode out and latch onto the face of whatever host they can find.
Once attached, the face-hugger then uses its victim’s mouth to implant an embryo inside the host’s body.
Yeah – pretty messed up.
Fortunately, face-huggers are only the stuff of science-fiction. Or are they?