This creature doesn't untap during your untap step.
At the beginning of your upkeep, you may pay . If you do, untap this creature.
Illustrated by Doug Chaffee · Mirrodin · #179
There are no rulings for Goblin War Wagon.
At the beginning of your upkeep, you may untap target tapped creature an opponent controls. If you do, untap this creature.
: Untap this creature. ( can be paid with one mana from a snow source.)
At the beginning of your upkeep, scry 1.
Whenever you cast a creature spell, you may pay . If you do, draw a card.
, : Put a +1/+1 counter on this creature. ( is the untap symbol.)
This creature attacks each combat if able.
Whenever another creature dies, untap this creature.
At the beginning of your end step, this creature phases out. (While it's phased out, it's treated as though it doesn't exist. It phases in before you untap during your next untap step.)