that actually happened to me once a while ago. I copped some "Hawaiian Punch" (strain name) from this shady dealer. Then after i smoked it with my boy we were sitting at a buss stop and i was feeling like i was zooming down a coaster then i aksed him and he said he was feeling the same sensation. The next day of a few days later we cop off the same kid and after 5 or 6 bowls in the bubler and a blunt or two sure enough we were getting that feeling again but this time it didnt end pretty. I was face down in his toilet for a good 20 mins before returning to a somewhat normal state.
we later found out this kid sprayed Raid (roach/ant killer) on the weed. That fuckin bastard.