Countermand

Oracle Text

Counter target spell. Its controller puts the top four cards of their library into their graveyard.

Card Rulings

4/26/2014 If the target spell is an illegal target when Countermand tries to resolve, Countermand won’t resolve and none of its effects will happen. The target’s controller won’t put any cards from the top of their library into their graveyard.
4/26/2014 You may target a spell that can’t be countered with Countermand. If you do, when Countermand resolves, the target spell won’t be countered, but its controller will still put the top four cards of their library into their graveyard.