AP: Strength of Night, Instant 2G Kicker {B} (You may pay an additional {B} as you cast this spell.) Creatures you control get +1/+1 until end of turn. ...

Strength of Night

Kicker B (You may pay an additional B as you cast this spell.)

Creatures you control get +1/+1 until end of turn. If this spell was kicked, Zombie creatures you control get an additional +2/+2 until end of turn.