According to this claim, the founder of Scientology, L. Ron Hubbard, allegedly received secret knowledge from extraterrestrial entities known as “Thetans” or “Xenu,” which forms a central part of Scientology’s advanced teachings. These theories suggest that the highest levels of Scientology, often referred to as Operating Thetan (OT) levels, involve accessing and dealing with this extraterrestrial knowledge and the influence of these beings.