Name:Forcefield
ManaCost:3
Types:Artifact
A:AB$ ChooseCard | Cost$ 1 | Choices$ Creature.unblocked | AILogic$ NeedsPrevention | SubAbility$ DBEffect | SpellDescription$ The next time an unblocked creature of your choice would deal combat damage to you this turn, prevent all but 1 of that damage.
SVar:DBEffect:DB$ Effect | ReplacementEffects$ RPreventDamage | SVars$ RPreventDamage,PreventDmg,ExileEffect | References$ PreventDmg,ExileEffect | SubAbility$ DBCleanup | ConditionDefined$ ChosenCard | ConditionPresent$ Card | ConditionCompare$ GE1

SVar:RPreventDamage:Event$ DamageDone | ValidSource$ Card.ChosenCard | ValidTarget$ You | ReplaceWith$ PreventDmg | PreventionEffect$ True | IsCombat$ True | Description$ The next time an unblocked creature of your choice would deal combat damage to you this turn, prevent all but 1 of that damage.
SVar:PreventDmg:DB$ ReplaceEffect | VarName$ DamageAmount | VarValue$ 1 | SubAbility$ ExileEffect
SVar:ExileEffect:DB$ ChangeZone | Defined$ Self | Origin$ Command | Destination$ Exile

SVar:DBCleanup:DB$ Cleanup | ClearChosenCard$ True
SVar:NonStackingEffect:True
SVar:Picture:http://www.wizards.com/global/images/magic/general/forcefield.jpg
Oracle:{1}: The next time an unblocked creature of your choice would deal combat damage to you this turn, prevent all but 1 of that damage.