well if someone has died in their acid trip and yet remained living i think they could answer that...
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And to answer the original question i cant say that iv ever died but i dont think this is even remotely possible. LSD isnt a special matrix (the movie) like world. Its just a different sence of perception with distortion. You could probably die or see your self dead and remain living. It just might screw up your head a bit.
Panda