lsd-25
In the 1960s, LSD-25 was lysergic acid diethylamide (on the mid-East Coast, anyway). AKA as "acid". Hallucinogenic, psychedelic drug. Usually just called "LSD".
Are you gonna drop LSD 25 this weekend? Yeah, I'm going to the LSD-25 church in Washington, DC! Its teachings are based on acid! Wow! What a rush!