[torified]

I was on acid, being driven by a friend in a car at night, and I saw the car ahead of us drive off the side of the road.

It didn't happen.

It was basically a daydream - I was just thinking to myself, "I hope that car doesn't crash", then zoned out and literally saw it happen with my eyes open. I watched the tail lights drive off the edge.

Afterwards I zoned back in and the car ahead of us was back.

That is the only time I've ever seen anything that wasn't actually there except patterns and "breathing". I haven't ever taken anything near a heroic dose though.