A human blockhead is a carnival or sideshow performer who hammers a nail or other implement (such as an ice pick, awl or screwdriver) into their nasal cavity via the nostril.
Over the years, several variations of the act have been developed by numerous performers, using objects including running power drills, fireworks, lit fire-eating rods, condoms, balloons, cork screws, letter openers, straws, spoons, forks, ice picks, and much more.
In 2005, scientific skeptic and investigator James Randi criticized faith healer John of God of Brazil for his use of this carnival trick to convince unsuspecting people, some desperately ill, of his paranormal healing powers.
[4][5] Randi and others also criticized news media outlets ABC, CNN, and Oprah Winfrey for uncritically promoting the faith healer's quackery.
The performer displays a large meat hook and then proceeds to force it into the nostril, through his nasal cavity and out his mouth.