At 20 hours? I used to do that regularly. Wake up at 6 am, work, party til 2 am on a Friday. I've never heard of anyone hallucinating in that short of a time. That only happens when you're up for like 3 days straight.
Did you… read the comment you’re replying to? Or just skip straight to writing the one-upper reply?
Do you mean besides intentionally because of the effects of drugs and/or alcohol?
(Before people come for me: I’m not saying alcohol causes hallucinations, more that it affects perception and makes it very difficult to figure out if you’re tired enough to hallucinate)