digging your own grave

When a character does something stupid or offensive with a lack of foresight and is about to be punished for it.

If the character is currently being punished or is suffering the aftermath of it, there's also Told You Not to Do That.
If the character is about to meet a bad end but not through their own stupidity, use Impending Doom instead.
If the character is aware of the aftermath and accepted it, you may put it in I Regret Nothing!! instead.