All yoga is preparation for meditation. Yoga is practiced in all forms of Hinduism. The most advanced forms of yoga involve siddhis, which give the practitioner God-like powers. Siddhis include tumo (the power to generate heat within the body), chulen (the power to live without eating food), the power to run long distances without stopping for rest, the power to become large/small or invisible, the power to read minds... the list is actually quite long.
The most advanced yoga involves lucid dreams and tulpa or thought form creation. The creation of other living beings (egregores, djinns, etc.) in real life may be included in these dream yoga efforts. Tulkus are individuals who are born through an immaculate conception (the Dalai Lama, the Panchen Lama, etc.). Tulkus are "willed" into existence by a mass population, when the time is ripe for them to come back to this world. Tulkus are essential tulpas that are born into a woman. Tulpas are born into manifest reality without relying on the body of a woman; it is far more direct. Tulpas may include any material object, and not just living beings. The ancient Bon religion (9,000+ years) and the Australian aborigine Dreamtime religion (60,000+ years) believe the same things.
Dream yoga involves the awakening of the third eye. Once awakened, this allows the practitioner to remain "awake" or mentally aware no matter what activity is going on... sleep, work, and even death. This is supposedly the same "eternal life" that Christ talked about. The mind remains alert and aware without the body.
Having experienced this state with the help of hallucinogens, I can tell you that the dull-colored smoke of Hell is right around the corner during these experiences. One must fight not to enter Hell.
These experiences ultimately led me to traditional Catholicism. I am no longer a pagan. I am a follower of Christ. I am here to provide warning.