Cheapest priced copy (Legends): $20.99 at Card Kingdom, near mint, their price list as of .
Life Matrix 
Artifact · Rare · Legends · #284
{4}, {T}: Put a matrix counter on target creature and that creature gains "Remove a matrix counter from this creature: Regenerate this creature." Activate only during your upkeep.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $20.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Legends | 284 | Rare | $20.99 | — |
One ruling from Wizards of the Coast
- 4 October 2004Once the counter is placed on the creature, the ability to remove it can only be activated by the player who controls the creature.