Flotsam // Jetsam

Oracle Text

[Flotsam]
Mill three cards. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

[Jetsam]
Each opponent mills three cards, then you may cast a spell from each opponent's graveyard without paying its mana cost. If a spell cast this way would be put into a graveyard, exile it instead.