1. A reference to the Woodstock Festival in 1969, when stage announcements were made by legendary radio disc jockey Wavy Gravy, telling people that some of the brown-colored blotter acid (LSD) circulating the crowd was giving people negative hallucinations, causing freakouts.
2. A bad drug experience
3. Something that was supposed to be pleasurable but turned out nightmarish.
1. I thought this job was going to be fun, but it turned out to be, like, "Dude, don't take the brown acid."
2. That chick is the brown acid, but hey, it's up to you.