5

Whenever Scarecrow stuns an attacker, return that character to owner's hand.
Whenever Scarecrow becomes stunned by a defender, return Scarecrow to owner's hand.
Boost X: When Scarecrow comes into play, return all characters with a cost of X or less your opponents control to owners' hands. For each character returned to hand this way, put two +1 ATK / +1 DEF counters on Scarecrow.