Cheapest priced copy (Kaldheim): $0.35 at Card Kingdom, near mint, their price list as of .
King Harald's Revenge 
Sorcery · Common · Kaldheim · #180
Until end of turn, target creature gets +1/+1 for each creature you control and gains trample. It 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 |
|---|---|---|---|---|
| Kaldheim | 180 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 5 February 2021If the creature attacks, the defending player must assign at least one blocker to it if that player controls any creatures that could block it. Other creatures may also block it, block other creatures, or not block at all.
- 5 February 2021Use the number of creatures you control as King Harald's Revenge resolves to determine how big the power and toughness boost is.