Enchantment
Planar Chaos
At the beginning of your upkeep, flip a coin. If you lose the flip, sacrifice this enchantment. Whenever a player casts a spell, that player flips a coin. If they lose the flip, counter that spell.
From Magic: The Gathering.
Exact printings
Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6oc3s38bajpb1hofbnzf7q.