Winter's Chill | Magic: The Gathering
Formats Winter's Chill is Legal in
Official Oracle Text for Winter's Chill
X can't be greater than the number of snow lands you control.
Choose X target attacking creatures. For each of those creatures, its controller may pay or . If that player doesn't, destroy that creature at end of combat. If that player pays only , prevent all combat damage that would be dealt to and dealt by that creature this combat.
Official Rulings for Winter's Chill
9/20/2013 : If a turn has multiple combat phases, this spell can be cast during any of them as long as it's before the beginning of that phase's Declare Blockers Step.