Roar of Jukai

Instant - Arcane, 2G (3)
If you control a Forest, each blocked creature gets +2/+2 until end of turn.
Splice onto Arcane-An 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.)¹
Illus. Ron Spencer

Gatherer Card Rulings [Nov 2009]

• 2/1/2005: Roar of Jukai can be cast even if you don't control a Forest or there are no blocked creatures. If you control no Forests or if there are no blocked creatures, the spell does nothing.

Format Legality	Legal in Vintage, Legacy, Extended Banned in Standard
Printings (1/8)	Betrayers of Kamigawa (Common)