Found this on Wiki… so you’re of course thinking that there’s no way this can be true. Check out the references, I’m pretty sure the story is trump tight.
The best-known portion of Scientology’s space opera is the myth of Xenu, known as “Incident 2”. Hubbard stated that there was a group of 76 planets around stars that are visible from Earth that organized in a Galactic Confederacy about 75 million years ago. Xenu, an evil and corrupt dictator, led the confederacy. The confederacy became overpopulated: each planet had 178 billion inhabitants. In an attempt to solve his overpopulation issue, Xenu placed several billion of his citizens onto DC 8 planes in refrigerators and sent the planes to the planet Teegeeack (now known as Earth). Hubbard stated that Xenu told the subjects that they were being transported there for tax auditing. When they arrived on Teegeeack, hydrogen bombs were detonated inside volcanoes, killing the aliens. After their deaths, their thetans were captured and brought to Hawaii and the Canary Islands, where Xenu’s priests and psychiatrists brainwashed them. These instructors lectured on invented ideas, such as the myth of Jesus, to deceive thetans about their nature. Eventually, a group of officers of the Galactic Confederacy launched a rebellion against Xenu. They pursued him for six years before capturing him and placing him in an electrified prison cell in the center of a mountain. Hubbard taught that the thetans who had been brainwashed by Xenu’s forces remained on Earth. When humans evolved, he said, the “body thetans” that had been wandering the Earth began to contribute human problems. He believed that individuals could be freed from these brainwashed thetans and thus attain a type of salvation.