The most profound trip I ever had was a result of my making a whole lot of LSA scum. I dried the stuff to a crispy powder and ate a horse cap full - when I felt nothing after an hour and a half, I figured that I must have destroyed the actives in the accelerated heat so I took some of the original orange sunshine, the yellow barrels - after another hour I began to feel the most extatic God illumiating rush - yes, an almost unbearable cell by cell extacy and transcendance joy I had ever felt or have ever felt afterward. It lasted several hours - no real hallucinations, just subtle distortions of vision that placed a halo around everything and tiny sparkles of light, beams eminating from each speckle but my mind was crystal clear. It was the most intense mental and physical rush of explosive energetic joy to the point where I was thinking that I might die of it and that death was absolutely welcome.
And then, the trip began and I was disassembled for the next 10 hours or so.
The other was a bit more hellish - I had a friend take some newly aquired acid, tiny gelatin pyramids, he ate two but I was still working on a thesis and had to delay my journey for two hours. My buddy was complaining that the stuff I gave him was weak so he took a third one and I, figuring that I had a break, that I would avoid half way measures that he was forced into, took all three at once.
Moments after I had done so he came on. For the next 5 hours I watched him grow more and more confused, he was lost in a wave and speaking incoherently getting higher with each wave. The problem was that I knew I was about an hour behind him and everyhing I watched him go through I knew was in store for me. He became the perfect predictor of what would happen to me. When he had trouble at a peak, I knew I would have the same trouble, when he rested at the trough, I, now at the peak, saw him far below and was forced to wait until I swooped down to where he was as he was swept away yet again, I knew my time was coming. The events grew more syncronized but I was still about half an hour after him the entire time. He became my sole focus in existance.
There is nothing like that sort of foreshadowing