Withdraw
Instant
Return target creature to its owner's hand. Then return another target creature to its owner's hand unless its controller pays 
.
"We outnumber them! Charge! Charge! Hey, where'd you guys go? Retreat! Retreat!"
Adam Rex
Prophecy (PCY)
• #54Rulings
You choose on announcement which creature is the one that can be paid to prevent the effect. The payment itself is made on resolution (if at all).
(wotc • 2004-10-04)
The creature’s controller gets the option to pay when the spell resolves.
(wotc • 2004-10-04)
The two creatures may have different controllers.
(wotc • 2004-10-04)
Must target two different creatures.
(wotc • 2004-10-04)
Rulings
You choose on announcement which creature is the one that can be paid to prevent the effect. The payment itself is made on resolution (if at all).
(wotc • 2004-10-04)
The creature’s controller gets the option to pay when the spell resolves.
(wotc • 2004-10-04)
The two creatures may have different controllers.
(wotc • 2004-10-04)
Must target two different creatures.
(wotc • 2004-10-04)