Name:Natural Order
ManaCost:2 G G
Types:Sorcery
A:SP$ ChangeZone | Cost$ 2 G G Sac<1/Creature.Green/green creature> | Origin$ Library | Destination$ Battlefield | ChangeType$ Creature.Green | ChangeNum$ 1 | AILogic$ SacAndUpgrade+SacWorst | AISearchGoal$ Creature.Green | SpellDescription$ Search your library for a green creature card and put it onto the battlefield. Then shuffle your library.
# AI Preference is needed to make the AI consider the ability. Further constraints are defined by AILogic SacAndUpgrade.
SVar:AIPreference:SacCost$Creature.Green
SVar:Picture:http://www.wizards.com/global/images/magic/general/natural_order.jpg
Oracle:As an additional cost to cast Natural Order, sacrifice a green creature.\nSearch your library for a green creature card and put it onto the battlefield. Then shuffle your library.