Battle at the Bridge

Feb 9, 2017 · When using improvise to cast a spell with {X} in its mana cost, first choose the value for X. That choice, plus any cost increases or decreases, will determine the spell’s total cost. Then you can tap artifacts you control to help pay that cost. For example, if you cast Whir of Invention (a spell with improvise and mana cost {X}{U}{U}{U}) and choose X to be 3, the total cost is {3}{U}{U}{U}. If you tap two artifacts, you’ll have to pay {1}{U}{U}{U}.

Feb 9, 2017 · Because improvise isn’t an alternative cost, it can be used in conjunction with alternative costs.

Feb 9, 2017 · Improvise doesn’t change a spell’s mana cost or mana value.

Feb 9, 2017 · If the target creature becomes an illegal target, Battle at the Bridge doesn’t resolve and none of its effects happen. You won’t gain life.

Feb 9, 2017 · Improvise can’t pay for {W}, {U}, {B}, {R}, {G}, or {C} mana symbols in a spell’s total cost.

Feb 9, 2017 · Tapping an artifact won’t cause its abilities to stop applying unless those abilities say so.

Feb 9, 2017 · Equipment attached to a creature doesn’t become tapped when that creature becomes tapped, and tapping that Equipment doesn’t cause the creature to become tapped.

Feb 9, 2017 · Improvise can’t be used to pay for anything other than the cost of casting the spell. For example, it can’t be used during the resolution of an ability that says “Counter target spell unless its controller pays {3}.”

Feb 9, 2017 · When calculating a spell’s total cost, include any alternative costs, additional costs, or anything else that increases or reduces the cost to cast the spell. Improvise applies after the total cost is calculated.