Wasp Zombifies Roach

A species of wasp called Ampulex compressa seems like your normal wasp, except when its female takes control of the mind of its prey and turn it into a zombie!

The wasp slips her stinger through the roach's exoskeleton and directly into its brain. She apparently uses sensors along the sides of the stinger to guide it through the brain ...

From the outside, the effect is surreal. The wasp does not paralyze the cockroach. In fact, the roach is able to lift up its front legs again and walk. But now it cannot move of its own accord. The wasp takes hold of one of the roach's antennae and leads it--in the words of Israeli scientists who study Ampulex--like a dog on a leash.

http://loom.corante.com/archives/2006/02/02/the_wisdom_of_parasites.php