Cheapest priced copy (Core Set 2019): $0.35 at Card Kingdom, near mint, their price list as of .
Nightmare's Thirst 
Instant · Uncommon · Core Set 2019 · #111
You gain 1 life. Target creature gets -X/-X until end of turn, where X is the amount of life you gained this turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Core Set 2019 | 111 | Uncommon | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 13 July 2018Nightmare’s Thirst counts how much life you’ve gained this turn, not how much your life total changed. For example, if you’ve gained 5 life and lost 8 before Nightmare’s Thirst resolves, Nightmare’s Thirst has you gain 1 more life, then it gives the target creature -6/-6.
- 13 July 2018If the target creature is an illegal target when Nightmare’s Thirst tries to resolve, the spell doesn’t resolve. You won’t gain 1 life.