Most of the time you don't really hallucinate. Not in the sense that you see actual 'things'. More like weird shit going on in your mind. Colours are brighter, strange sounds and enhanced perception.
Can be a trip thru cartoonville tho but you never know until it's too late how it's going to go. I grew up in Vancouver, BC and was getting really good acid back in the late 60s, early 70s. Thousand hits of blotter for $250 and half a hit would have you talking to god. Used to shine a black light on the sheets of blotter to cut it up. Some dots were bright which meant they were well soaked and others looked dim so each hit was a different strength. Sometimes a big blob would be there like they spilled some so if you got a piece of that you could get really f'ed up. Quality control was pretty lax.
My first trip was a big cap of Purple Haze when I was 14. Spent the day wandering around Stanley Park with the older hippies that turned me on. By older I mean 17 -19 or so. Lots more after that. White micro-dot, orange wafer, window pane, purple double-dome etc. Even soaked blotter in a spoon of water and injected it. From earth to orbit in 5 sec flat! lol
It's the mind fuck that can really trip you out. Can make you feel like Superman or like the dregs of the world. A good friend of mine took it once and emerged different. His mind took a weird turn and he was never the same. Was raised a strict Mennonite so maybe that had something to do with it but he went off the deep end. He died a few months back and had sent me a voice call on Facebook I didn't get until after he passed. Hadn't seen or heard from him in at least 20 years. More like 30. They found him dead in his easy chair with remote in hand. Heart attack. Not a bad way to go tho.