Mirrored Depths

Whenever a player casts a spell, that player flips a coin. If the player loses the flip, counter that spell. Whenever chaos ensues, target player reveals the top card of their library. If it's a nonland card, you may cast it without paying its mana cost.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6o3m251gm7pb1hkqb739b5.