Plane — Karsus
Whenever a player casts a spell, that player flips a coin. If he or she loses the flip, counter that spell.
Whenever you roll , target player reveals the top card of his or her library. If it's a nonland card, you may cast it without paying its mana cost.
Planechase Anthology (PCA)
Illustrated by: Chippy
Multiverse ID: 423632