Lazav, the Multifarious is a rare Legendary Creature — Shapeshifter card from Ravnica Remastered (RVR), collector number 371. Current market price: $0.35 (foil $0.34), TCGplayer market prices via Scryfall.
When Lazav enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.) {X}: Lazav becomes a copy of target creature card in your graveyard with mana value X, except its name is Lazav, the Multifarious, it's legendary in addition to its other types, and it has this ability.