Considering we're on a forum called Roll It Up, in the hallucinatory substances section, in a thread titled "your fav drug", maybe we should remove MJ from the list of possible answers?
I do not consider Marijuana a "drug" as the contemporary term is used, just as many do not consider alcohol, or their prescription medications, a drug; Even though they have mind altering effects
#1 being LSD, followed by
#2 MDMA
#3 is a toss up between a combination of the above listed or LSD and ketamine
to have a #4 may be overkill in a favorites thread, but it would be a synthetic cannabinoid (not really my first choice, but its helping me pass drug screens while looking for a job without being miserably sober every day)