Alien invasion.

Truth is sometimes stranger than science fiction. One example: French scientists discovered that a tiny worm can brainwash a cricket into taking a deadly swim.

The hairworm, or Spinochordodes tellinii (SPIN-no-cor-DOH-dis TELL-ee-nee), is a parasite that depends on insects for its survival. As a larva, the developing worm lodges itself inside a cricket and feasts on the insect's innards. The squirmy parasite eats its host carefully, keeping the cricket alive until the worm reaches adulthood, explains Frederic Thomas, a biologist at the French National Center for Scientific Research.

But when the parasite is mature and ready to mate, it needs to relocate to a freshwater home. So the worm injects a chemical into the cricket's brain, causing the insect to behave bizarrely: The normally land-dwelling cricket searches for water, plunges in, and drowns. Then, the worm crawls out of its host's body and swims away to find a mate.