The loser films a full local-news-style weather segment, gestures at an imaginary map, five-day forecast, station sign-off, about the 'climate' of their fantasy season: cold streaks, droughts at running back. Posted publicly. The blazer makes it art.
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: fantasypunishments.com