Instant — Trap, 3WW (5)
Uncommon
If four or more creatures are attacking, you may pay {1}{W} rather than pay Arrow Volley Trap's mana cost.
Arrow Volley Trap deals 5 damage divided as you choose among any number of target attacking creatures.
Illus. Steve Argyle

10/1/2009: You may ignore a Trap's alternative cost condition and simply cast it for its normal mana cost. This is true even if its alternative cost condition has been met.
10/1/2009: Casting a Trap by paying its alternative cost doesn't change its mana cost or converted mana cost. The only difference is the cost you actually pay.
10/1/2009: Effects that increase or reduce the cost to cast a Trap will apply to whichever cost you chose to pay.
10/1/2009: The number of targets must be at least 1 and at most 5. You divide the damage as you cast Arrow Volley Trap, not as it resolves. Each target must be assigned at least 1 damage.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Extended (Type 1.X)
Legal in Classic (MTGO)
Legal in Commander
Legal in Modern