Siren, Aquatic Phantom Queen (WXDi-P10-035[EN]) [Prismatic Diva]

[Const]: As long as this SIGNI is awakened, it gets +1000 power and gains “[Auto]: When this SIGNI leaves the field, you may pay (W). If you do, return target SIGNI on your opponent’s field to its owner’s hand.”

[Auto]: At the beginning of your attack phase, if you have four or more cards in your hand, this SIGNI is awakened. (SIGNI stay awakened for as long as they remain on the field.)