Dewloren, Tiger King of the Ice Barrier (HA02-EN027) - Hidden Arsenal 2 Unlimited

1 Tuner + 1 or more non-Tuner WATER monsters // Once per turn, you can return any number of face-up cards you control to the owner's hand. This card gains 500 ATK for each card returned to the owner's hand by this effect until the End Phase of this turn.