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At the beginning of your upkeep, sacrifice Thelon's Chant unless you pay {G}.
Whenever a player puts a Swamp onto the battlefield, Thelon's Chant deals 3 damage to that player unless the player puts a -1/-1 counter on a creature they control.
Damages the player putting the land onto the battlefield, even if they are not the controller of the land after it is on the battlefield.
