Cheapest priced copy (Adventures in the Forgotten Realms): $0.35 at Card Kingdom, near mint, their price list as of .
Compelled Duel 
Sorcery · Common · Adventures in the Forgotten Realms · #178
Target creature gets +3/+3 until end of turn and must be blocked this turn if able.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Adventures in the Forgotten Realms | 178 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 23 July 2021Only one creature is required to block the affected creature. Other creatures may also block it and are free to block other creatures or not block at all.
- 23 July 2021If each creature the defending player controls can't block for any reason (such as being tapped), then the affected creature isn't blocked. If there's a cost associated with blocking the affected creature, the defending player isn't forced to pay that cost, so it doesn't have to be blocked in that case either.