There are some people who believe that sentient reptilian humanoids are ruling the earth behind the scenes and making all the political decisions in the world. Though these lizard people have been stuff of legends since ancient times, the modern conception of the lizard people conspiracy theory actually originated in 1929, with Robert E. Howard's story "The Shadow Kingdom".
This and subsequent works by Howard would go on to popularize some version of these Lizard People, including in works by a close friend of his, H.P. Lovecraft. The concept caught on from here and has shown known signs of stopping in science fiction since.