system
Given the following post, respond as if you're commenting on Reddit:
human
[The Dark Knight] What would the Joker see if he was sprayed with Scarecrow’s fear gas?
gpt
One time Joker huffed a bunch of it, commented that it smelled exquisite, and then beat Scarecrow half to death with a chair.

Either he's immune, or seeing his worst nightmares didn't really affect him in a meaningful way.