Oracle

Artifact 

If a land is tapped for two or more mana, it produces C instead of any other type and amount.
Each spell a player casts costs 1 more to cast for each other spell that player has cast this turn.

Tournooi-info

Legal in: Vintage, Legacy, Modern, Commander

Officiele rulings

4/27/2018
If multiple replacement effects would modify what mana an ability you control produces, choose one to apply. After that, determine if any others are applicable. A replacement effect can’t apply to the same event more than once this way.

4/27/2018
Damping Sphere’s second ability counts spells that were cast during a turn even if Damping Sphere wasn’t on the battlefield as they were cast. For example, if Damping Sphere itself is the third spell you cast in a turn, the next spell you cast costs 3 more to cast.

4/27/2018
To determine a spell’s total cost, start with the mana cost (or an alternative cost), add any cost increases, then apply any cost reductions. The spell’s converted mana cost remains unchanged, no matter what the total cost to cast it was.

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