Valkyr, Space Angel

Flying, First Strike, Lifelink
When Valkyr, Space Angel enters the battlefield
you may sacrifice up to two other creatures you
control, if so you may return two creatures from
your graveyard to the battlefield.
Valkyr, Space Angel's power is equal to the
combined power of all other creatures you
control. Valkyr, Space Angel's toughness is equal
to your life total.