Cheapest priced copy (Commander 2014): $0.35 at Card Kingdom, near mint, their price list as of .
Tendrils of Corruption 
Instant · Common · Magic 2010 · #114
Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
10 printings · $0.35 to $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2014 | 166 | Common | $0.35 | — |
| Duel Decks: Garruk vs. Liliana | 54 | Common | $0.35 | — |
| Duel Decks: Phyrexia vs. the Coalition | 30 | Common | $0.35 | — |
| Duel Decks: Nissa vs. Ob Nixilis | 63 | Common | $0.35 | — |
| Foundations Commander | 128 | Common | $0.35 | — |
| Duel Decks Anthology: Garruk vs. Liliana | 54 | Common | $0.35 | — |
| Magic 2010 | 114 | Common | $0.35 | $3.99 |
| The List | C14-166 | Common | $0.35 | — |
| Time Spiral | 136 | Common | $0.35 | $1.99 |
| Time Spiral Remastered | 145 | Common | $0.35 | $0.79 |
One ruling from Wizards of the Coast
- 19 March 2021If the target creature is an illegal target by the time Tendrils of Corruption tries to resolve, the spell doesn't resolve. You don't gain X life.