Saguaro cactus are the largest cactus that grow in the United States. They are indigenous to the Arizona-Sonora Desert and do not grow at altitudes above about 3000 feet above sea level. A cactus this size can weigh several tons and there is a report of man being killed by a saguaro plant when he shot off one of the arms with a shotgun. Unfortunately, this is not an urban legend. The event happened in 1982. You can read about in this news article:"It's a sad but true tale: Man fatally crushed by saguaro."