Clostridium botulinum bacteria produce a potent neurotoxin called botulinum toxin, which causes the serious illness botulism. The toxin attacks the nervous system, leaving the body unable to control its muscles and making every breath a struggle. Without immediate treatment, botulism can be fatal. Humans, however, have managed to domesticate this dangerous bacterium to do their bidding. Over more than 90 years, biologists have been able to turn a wild microbe into an efficient factory for medical, military and cosmetic products like Botox.