Glorious End is a mythic Instant card from Amonkhet (AKH), collector number 133. Current market price: $1.20 (foil $2.48), TCGplayer market prices via Scryfall.
End the turn. (Exile all spells and abilities from the stack, including this card. The player whose turn it is discards down to their maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.) At the beginning of your next end step, you lose the game.