Clairvius Narcisse (January 2, 1922 – 1994) was a Haitian man who claimed to have been turned into a zombie by a Haitian Vodou, and forced to work as a slave. One hypothesis for Narcisse's account was that he had been administered a neurotoxin such as the paralyzing pufferfish venom tetrodotoxin, which rendered him helpless and seemingly dead. The greatest proponent of this possibility was Wade Davis, a graduate student in ethnobotany at Harvard University.
https://en.wikipedia.org/wiki/Clairvius_Narcisse