Culling Mark - mtg.wtf

2014-02-01 The controller of the creature chooses which attacking creature that creature blocks.
2014-02-01 The creature blocks only if it's able to do so as the declare blockers step begins. If, at that time, the creature is tapped, it's affected by a spell or ability that says it can't block, or no creatures are attacking its controller or a planeswalker controlled by that player, then it doesn't block. If there's a cost associated with having the creature block, the player isn't forced to pay that cost. If that cost isn't paid, the creature won't block.

Card is in preconstructed decks:

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