Bob Lazar is an American businessman and conspiracy theorist known for his claims about working on reverse-engineering extraterrestrial technology at a site near Area 51. He first gained public attention in the late 1980s when he alleged that the U.S. government was hiding information about UFOs and advanced spacecraft. Lazar's assertions include details about a propulsion system he claims to have seen, which utilized a substance he called Element 115. His controversial statements have sparked debates about government secrecy and the existence of UFOs, making him a prominent figure in discussions about alien technology and conspiracy theories.