Cheapest priced copy (Revised Edition): $0.35 at Card Kingdom, near mint, their price list as of .
Unstable Mutation 
Enchantment — Aura · Special · Time Spiral Timeshifted · #33
Enchant creature
Enchanted creature gets +3/+3.
At the beginning of the upkeep of enchanted creature's controller, put a -1/-1 counter on that creature.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
9 printings · $0.35 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Revised Edition | 86 | Common | $0.35 | — |
| Fourth Edition Foreign Black Border | 110 | Common | — | — |
| Fourth Edition | 110 | Common | $0.35 | — |
| Fifth Edition | 131 | Common | $0.35 | — |
| Arabian Nights | 22 | Common | $2.99 | — |
| Foreign Black Border | 86 | Common | — | — |
| Summer Magic / Edgar | 86 | Common | — | — |
| Time Spiral Timeshifted | 33 | Special | $0.35 | $2.99 |
| Ultimate Masters | 80 | Uncommon | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 1 August 2005The -1/-1 counters stay even if the Aura is removed, and the +3/+3 goes away when the Aura does.