I took way too much of a psychedelic at a concert a little over a year ago. Started out fine, I was coming up very quickly...and also very quickly the concert seemed to be getting more and more overwhelmingly crowded. Eventually I just laid back and allowed my senses to take in information because I was so overwhelmed...and then I blacked out.
The rest of the story is what I was told by my brother and friends. Apparently I stood up ran up to some random dude and started squeezing his face screaming about how I was dying. I got pulled off by my brother. I threw myself to the ground and started to eat the grass. I actually know why I ate the grass though, in my little semi-void I was having the thought that I needed to ground myself, and while I was eating the grass the contents of plants cells were going through my head.
Anyway, that didn't do the trick and I started army crawling up the grass hill that the majority of the concert-goers were. I ended up crawling right into the middle of a fight that two drunk people were having, the fight stopped and people were just circled around me watching me freak out, apparently some people were kicking me.
Finally my brother and friends find where I had escaped to and pulled me away. Some random girl that I didn't know started trying to hold me down and I ended biting my brothers leg really hard leaving big teeth marks.
Eventually the paramedics get there, it takes 4 or 5 of them to wrestle me down and carry me out of the concert into a tent. As soon as the gave me some haldol(antipsychotic) I immediately came down. First thing I remember (besides thoughts of grass) was one of the medics saying "woooh you musta been tripping hard" and my laughing histerically at this.