Less a punishment than a delivery mechanism: the league holds a formal courtroom ceremony, robe, gavel, charges read aloud, where the loser's punishment is revealed and accepted. Turns the assignment itself into content. Pleading for leniency adds a second charge.
Budget note: this one costs nothing but dignity, which makes it a strong pick for leagues that would rather spend the pot on the champion than on the loser's downfall.
Seen in the wild: scoutcast.ai