Could be sleepwalking. Could also be a form of childhood epilepsy. My son had partial seizures for many years. Unlike the full-blown seizures that
wrack and shake the whole body and typically cause a loss of consciousness, partial seizures affect only a portion of the brain (hence the name) and
can be behavioral in nature.
My son did some very strange things, mostly nocturnal, including sitting up in bed, swinging his arms and repeatedly yelling, "I'm the President of
the United States;" pooping in the middle of my office floor, and transporting invisible objects with large sweeping motions.
Many neurologists believe that patterns -- such as the ones found in video games, wallpaper, strobe lighting, or the "snow" on your tv -- can induce
seizures in individuals who are prone to them. I wouldn't worry too much about it, or read too much into it. Most people hwo have such episodes in
childhood simply outgrow them.
On a lighter note, having had a baby via natural childbirth I can tell you most emphatically that it's an "out-of-body experience!"