Cheapest priced copy (Foundations): $0.35 at Card Kingdom, near mint, their price list as of .
Felling Blow 
Sorcery · Uncommon · Foundations · #105
Put a +1/+1 counter on target creature you control. Then that creature deals damage equal to its power to target creature an opponent controls.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Foundations | 105 | Uncommon | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 8 November 2024As Felling Blow tries to resolve, if either creature is an illegal target, the creature you control won't deal damage. If the creature you control is a legal target but the other creature isn't, your creature will still get a +1/+1 counter.
- 8 November 2024You can't cast Felling Blow unless you choose a creature you control and a creature an opponent controls as targets.