sorta the same thing happened to me, this guy i knew from a while back passed me his bowl( i was smoking in a park with some friends and he passed by and offered me his bowl) I as the good pothead I am didnt think it twice before i grabbed the pipe and hit it, after a few hits i start feeling dizzy and my heart was pumping very fast, i let him know this and asked him whether that bowl was laced or not. I knew him from the days that he only smoked grass but then he moved on to crack, there was no other answer than saying he offered me a bowl of weed laced with crack, whilst he denied that he had laced the bowl with crack. pretty funky 15 minutes i felt after the effects subdued, it remained a mystery if the bowl was really laced with crack or if it was my psyche that was fucking around me