on a bad one

when someone is so intoxicated or high on drugs that they don't know what they are doing, and consequently do something stupid or extremely illegal.

Gorge:Jamal where did you get all of this stolen shit?!?!
Jamal:I don't even know dog... I was on a bad one last night.

Tony:Dude did you really fuck that ugly ass girl?
Jack:Probably I was on such a bad one though...