system
A chat on subreddit /r/wallstreetbets
human
Not straight short stock, or buy puts/sell naked calls or whatever you want to see as 'normal' shorting of a company, but surely through some sort of *exotic* derivative a bank could essentially short itself.  Maybe not legally, but if 2008 taught me anything is the banks can basically ruin the world economy and you might have a few folks go to jail.

gpt
Might if you are in finland, otherwise you get bonuses for doing it.