Crab of Omens

, : Put target green creature on top of its owner's library.

As this creature enters, choose a color. All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

Players can't draw cards. At the beginning of each player's draw step, that player exiles the top card of their library. If it's a land card, the player puts it onto the battlefield. Otherwise, the player casts it without paying its mana cost if able.