Definition
Exaggerated, bizarre or unpredictable.
Origins
From on + acid, referring to the intoxicating substance.
How People Actually Use It
A term that can be used alongside a person, place or thing to describe a particular event or situation that is very similar though highly exaggerated.
""I went to see that comedy show the other night. The guy was like Jim Carrey on acid." "That disco was like the 80s on acid.""
Source: Urban Dictionary