The loser stands at a busy intersection for a set number of hours holding a sign that says 'I STINK AT FANTASY FOOTBALL, HONK IF YOU AGREE'. Every honk is a tiny dagger. Costume add-ons, a rival jersey or full football pads, are common multipliers.
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.