Amulet of Quoz is a rare Artifact card from Ice Age (ICE), collector number 308. Current market price: $1.58, TCGplayer market prices via Scryfall.
Remove this card from your deck before playing if you're not playing for ante. {T}, Sacrifice this artifact: Target opponent may ante the top card of their library. If they don't, you flip a coin. If you win the flip, that player loses the game. If you lose the flip, you lose the game. Activate only during your upkeep.