Fox offering (You may cast this card any time you could cast an instant by sacrificing a Fox and paying the difference in mana costs between this and the sacrificed Fox. Mana cost includes color.)
Whenever a creature attacks, you may gain 1 life.
You may gain life when any creatures are declared as attackers, not just for attacking creatures you control.
You may gain one life per attacking creature when the ability resolves during each declare attackers step.