Fleeting Spirit

{W}, Exile three cards from your graveyard: This creature gains first strike until end of turn.
Discard a card: Exile this creature. Return it to the battlefield under its owner's control at the beginning of the next end step.

Innistrad: Double Feature

Innistrad: Crimson Vow

If you activate Fleeting Spirit's first ability to give it first strike, you can later activate its last ability to remove it from combat after first strike combat damage is dealt but before normal combat damage is dealt.