Used to take quite high doses of LSD, and often had incredible visual hallucinations. Things like watching a large plant sprout flower buds all over it, which slowly expanded to full bloom and then retreated back to small buds; the whole experience went on like that for 20 minutes. Another time I hallucinated that a neighbor's house was on fire, until my friend said she was hallucinating the same thing. Fortunately, the fire brigade showed up quickly to quench the very real flames, without us having to ring them.