Nexus of Fate is a mythic Instant card from Special Guests (SPG), collector number 122. Current market price: $7.75 (foil $11.89), TCGplayer market prices via Scryfall.
Take an extra turn after this one. If Nexus of Fate would be put into a graveyard from anywhere, reveal Nexus of Fate and shuffle it into its owner's library instead.