Pitfall Trap
Instant — Trap
If exactly one creature is attacking, you may pay rather than pay this spell's mana cost.
Destroy target attacking creature without flying.
Each spike is poisoned—the trapmaker's idea of mercy.
Franz Vohwinkel
Rulings
Casting a Trap by paying its alternative cost doesn't change its mana cost or mana value. The only difference is the cost you actually pay.
(wotc • 2009-10-01)
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.
(wotc • 2009-10-01)
Effects that increase or reduce the cost to cast a Trap will apply to whichever cost you chose to pay.
(wotc • 2009-10-01)
Rulings
Casting a Trap by paying its alternative cost doesn't change its mana cost or mana value. The only difference is the cost you actually pay.
(wotc • 2009-10-01)
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.
(wotc • 2009-10-01)
Effects that increase or reduce the cost to cast a Trap will apply to whichever cost you chose to pay.
(wotc • 2009-10-01)