Graham has described what happens when he drink Ayahuasca. The activ drug in ayahuasca is a molecul called DMT The DMT alters the brain, as if the brain send and recieve in another frequency. Just as when you turn the knob on a radio. The surroundings "disappear". As if it is not there, and he gets into another realm or dimension, with other entities. This is explained by Rick Strassmann who has been researching DMT under controlled circumstanses.
This is a way to alter the mind, but what about altering the physical body? Teleportation is about that, and on can imagine once in the future that it is possible to alter both mind and body. I believe that is what Egyptian mythology is about. I believe Laurence Gardener was on the track.