Codex Shredder is a uncommon Artifact card from Return to Ravnica (RTR), collector number 228. Current market price: $0.35 (foil $5.22), TCGplayer market prices via Scryfall.
{T}: Target player mills a card. (They put the top card of their library into their graveyard.) {5}, {T}, Sacrifice this artifact: Return target card from your graveyard to your hand.