Name:Monstrous Onslaught
ManaCost:3 G G
Types:Sorcery
A:SP$ DealDamage | Cost$ 3 G G | ValidTgts$ Creature | TgtPrompt$ Select target creature to distribute damage to | NumDmg$ OrigPower | TargetMin$ Min | TargetMax$ OrigPower | References$ Min,OrigPower | DividedAsYouChoose$ OrigPower | SpellDescription$ CARDNAME deals X damage divided as you choose among any number of target creatures, where X is the greatest power among creatures you control as you cast CARDNAME.

T:Mode$ SpellCast | ValidCard$ Card.Self | Static$ True | Execute$ CountPowerAtCast
SVar:CountPowerAtCast:DB$ StoreSVar | SVar$ OrigPower | Type$ Count | Expression$ GreatestPower_Creature.YouCtrl

SVar:OrigPower:Count$GreatestPower_Creature.YouCtrl 

SVar:Min:SVar$OrigPower/LimitMax.1 
SVar:X:Count$GreatestPower_Creature.YouCtrl 
SVar:Picture:http://www.wizards.com/global/images/magic/general/monstrous_onslaught.jpg
Oracle:Monstrous Onslaught deals X damage divided as you choose among any number of target creatures, where X is the greatest power among creatures you control as you cast Monstrous Onslaught.