Roar of Jukai (Betrayers of Kamigawa)

Instant Ñ Arcane - If you control a Forest, each blocked creature gets +2/+2 until end of turn.
Splice onto ArcaneÑAn opponent gains 5 life. (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)