Credit: ABC News

I've been lots of weird places thanks to this job - I've been to war in Iraq, I've been to the top of an Icelandic volcano DURING an eruption, I've been in deadly earthquakes, tsunamis - all kids of crazy places. But this is the first time I left my body and went somewhere so profound, it took me hours to shake the feeling and return to my normal self.

I wasn't on drugs, I was in a sensory deprivation chamber at Float Seattle, an isolation tank center located in Seattle. It wasn't at all like the movie "Altered States" and thankfully I didn't regress into a monkey.

Here's the deal - I was assigned to do a story about the growing phenomenon of people using "float" tanks to meditate, relax, heal a sore back - all kinds of reasons. But the only way to truly grasp the experience was to try it. No problem, I figured it would be like getting paid to relax, daydream and maybe even nap. Let me tell you - it was not what I expected.

I'm floating in 10 inches of warm water, it's perfectly buoyant thanks to hundreds of pounds of Epsom salts. There is no light, no sound and I'm essentially in a pitch black box. When you float for the hour-long session, which costs $79, you go naked, or in a bathing suit, and because the water is so buoyant, you generally hold your arms over your head. You have earplugs in to keep the water out and only a small part of your face is above water.

So here I am, aware that I'm doing a story, aware that some people hallucinate in here and aware that I need to mentally record my experiences for the sake of the story. That's a lot of self awareness, what could possibly happen? At first, claustrophobia is what happens. Wow do I want to get out of there. Mainly, because the air is humid and only a small portion of my face is above water, I just really want to sit up and catch my breath. I fight the urge. Next I notice that I seem to be moving-a lot. In reality, I'm drifting an inch or two within the tank, but because I have no point of reference - it's so dark there's no difference between eyes open and closed - it's just the sensation that leaves me feeling like I'm rushing down a river. OK that's cool, a little weird, something to keep in mind for the story. I see a couple of white flashes too, but they're not much different from what you might experience sometimes when you shut your eyes tight.

After about a half hour of this and still wide awake, something unexpected happens. I'm suddenly in my childhood home, back in Michigan. You know those movie flashbacks where people remember things in crazy detail? That never happens in real life. But in the tank, floating there in the darkness, it was happening to me. I started going through every inch of my childhood home - a place I haven't seen in decades - in ridiculous detail. And I could control where I wanted to go. The kitchen and the little bed our family dog, Dusty used. My brother's room and all the cool trinkets on his dresser. My childhood desk, the lamp with the finicky switch. Let's look in my drawers - it's all there in crystal clear detail. I could not have recalled these things earlier if you'd asked me. Even more strange, I was aware that this was happening, but unlike a dream, I didn't lose it when I became aware of it. I even sneezed at one point and was worried it would all be gone, leaving me with the taste of something incredible that I would never have again. It wasn't. I scoured every inch of that house, even tattered board games hidden away in a closet, my old hockey stick in the garage, my sister's white 10-speed.

Now, when you float, you go for an hour and music gently begins to play to let you know when time is up. Just as the music was coming on, I was squeezing into the old chair my dad used to sit in each night to read the paper and watch TV. When I was very small, I could just barely fit in there with him. My dad passed away in 2010, but suddenly I was back in the chair right alongside him. I hadn't looked up to see his face yet or to speak, but I knew that was coming. As the music played, I was torn, it was all so real, but I'd already gone over my time and I knew my colleagues were waiting. I reluctantly opened the hatch and came back to reality - a "Nightline" team and video camera were waiting. I wasn't anxious to face them and knew that I was different than the sarcastic reporter they expected to see pop out.

Was it a dream? No, definitely not. And I wanted to go back.

Tune in to "Nightline" at 12:35 a.m. ET to watch ABC's Neal Karlinsky's full report.