When Unshakable Tail enters the battlefield and at the beginning of your upkeep, surveil 1 (Look at the top card of your library. You may put that card into your graveyard.). Whenever one or more creature cards are put into your graveyard from your library, investigate (To investigate, create a colorless Clue token. It's an artifact with ", Sacrifice this artifact: Draw a card."). , Sacrifice a Clue: Return Unshakable Tail from your graveyard to your hand.