The emerald cockroach wasp stings the cockroach in the brain in order to inject a specialized venom that takes control of the cockroach's decision making processes.
...When looking for a host, one of these parasitic wasps will start by stinging the midsection of a roach, and their toxic venom will paralyze the animal's front legs for five minutes. With a secondary strike, the wasp will go directly for the brain, where the sting will induce an intense 30-minute period of vigorous grooming.
NewsUrl: The Mind-controlling Molecules of Wasp Venom Could Help Future Parkinson's Research