The Mewtwo (12 / 113) card can be found in the Delta Species set.
Recently sold 5 times and based on those sales is worth around £30.00.
Currently, there are 13 open listings for this card on ebay.
This card sells in the range of £3.29 to £56.71, making it highly volatile.
This Rare Holo card was illustrated by Ryo Ueda.