a very high dose of LSD disguised as a single hit. A 'purple jesus' contains between 100 and 500 regular LSD doses. It is sometimes given to a someone as a practical joke or even punishment, since the person is likely to never be the same way again.
That turned out to be a Purple Jesus, not some regular weekend trip. 'Nice knowing you', were the last words I heard from the person who gave it to me.