That was interesting.
Hallucinogens produce all sorts of effects: objects glowing, lit cigarettes leaving streaks in the air as you move them around, things having iridescent colors to them, etc. The ones you don't want are bodies crawling out of ditches, hanging from buildings, things like that. If the person with you is tripping, too, then asking him if that stuff is real is useless. He'll just see it, too.