Cheapest priced copy (Wilds of Eldraine): $0.35 at Card Kingdom, near mint, their price list as of .
Gnawing Crescendo 
Instant · Common · Wilds of Eldraine · #131
Creatures you control get +2/+0 until end of turn. Whenever a nontoken creature you control dies this turn, create a 1/1 black Rat creature token with "This token can't block."
Legal inCommanderBrawlStandardPioneerModernLegacyVintagePauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Wilds of Eldraine | 131 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 1 September 2023Only creatures you control when Gnawing Crescendo resolves will get +2/+0. However, if a nontoken creature enters the battlefield after Gnawing Crescendo resolves and then dies while under your control later that turn, you'll create a Rat token.