Oracle

Enchantment 

Cumulative upkeep 1 (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
At the beginning of your upkeep, put a rust counter on each artifact target opponent controls. Then destroy each artifact with converted mana cost less than or equal to the number of rust counters on it. Artifacts destroyed this way can't be regenerated.
When Corrosion leaves the battlefield, remove all rust counters from all permanents.

Tournooi-info

Legal in: Vintage, Legacy, Commander

Officiele rulings

10/4/2004
It does count rust counters put on artifacts by other Corrosion cards. This means that having more than one of these can result in fast destruction of artifacts.

10/4/2004
In multiplayer games, you can choose a new target player each upkeep.

2/1/2006
Only puts rust counters on artifacts your opponents control, but destroys all artifacts with rust counters on them, even your own. When it leaves the battlefield, it removes all rust counters, not just those that happen to be on artifacts.

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