Sabina, of the Nightingale

{t}: {g} or {b}
Whenever an elf you control taps
to add mana to your mana pool,
mill cards equal to the mana added this way.
Each elf that is milled into your graveyard gains Flashback till the end of turn. The flashback cost is equal to its mana cost. Cast from your graveyard only if you didn't deal combat damage last turn.