Mnemonic Deluge is a mythic Sorcery card from Commander Legends (CMR), collector number 82. Current market price: $8.16 (foil $9.84), TCGplayer market prices via Scryfall.
Exile target instant or sorcery card from a graveyard. Copy that card three times. You may cast the copies without paying their mana costs. Exile Mnemonic Deluge.