Cheapest priced copy (Duel Decks: Jace vs. Vraska): $0.35 at Card Kingdom, near mint, their price list as of .
Grisly Spectacle 
Instant · Common · Modern Masters 2017 · #73
Destroy target nonartifact creature. Its controller mills cards equal to that creature's power.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
4 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duel Decks: Jace vs. Vraska | 75 | Common | $0.35 | — |
| Gatecrash | 66 | Common | $0.35 | $0.49 |
| Iconic Masters | 92 | Common | $0.35 | $0.49 |
| Modern Masters 2017 | 73 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 17 November 2017If the creature is an illegal target when Grisly Spectacle tries to resolve, it won’t resolve and none of its effects will happen. The creature’s controller won’t put any cards into their graveyard.
- 17 November 2017Use the creature’s power the last time it was on the battlefield to determine how many cards its controller puts into their graveyard.