Cheapest priced copy (Commander Legends): $0.35 at Card Kingdom, near mint, their price list as of .
Spontaneous Mutation 
Enchantment — Aura · Common · Innistrad Remastered · #86
Flash
Enchant creature
Enchanted creature gets -X/-0, where X is the number of cards in your graveyard.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Legends | 100 | Common | $0.35 | $0.49 |
| Eldritch Moon | 74 | Common | $0.35 | $0.49 |
| Innistrad Remastered | 86 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 10 November 2020The value of X will constantly update as the number of cards in your graveyard changes.