Ever smoke pot that was laced with something???

I'm 49 and I did ONLY ONCE. I remember, I was in high school - about 16 yrs old. We smoked behind the gym back then - bunch of us. I shared one joint.....it was lunchtime. All of a sudden I saw people's outlines only -- I was soooo thirsty and couldn't get to a fountain. I thought I was going to p out. It was horrible. I have had people tell me it was probably laced with LSD or something -- anything like this ever happen to you? Only once for me, It's freaky when you look at a human being and only see their outline...have you ever experienced this??? If not, have you smoked and it was laced and what happened????