Tyvar, Boasting Rallier

Menace, haste

You may activate abilities of other creatures you control as though those creatures had haste.

Boast — Sacrifice a creature or discard a card:
Mill three cards, then you may return a creature card with mana value 2 or less from your gaveyard
to the battlefield. (Activate this ability only if this creature attacked this turn and only once each turn.)