Gyarados is card #26 of 123 in Mysterious Treasures (2007), a Rare illustrated by Mitsuhiro Arita. At about $41.98 it is the #13 most valuable card in the set. In a Mysterious Treasures booster it turns up about once every 32 packs. It is one of 57 Gyarados cards printed so far.
1999Base Set
2002Legendary Collection
2006Holon Phantoms
2007Mysterious Treasures
2009Platinum
2013Legendary Treasures
2017Crimson Invasion
2021Evolving Skies

















See the full Mysterious Treasures card list
An ungraded Gyarados from Mysterious Treasures sells for about $41.98. A PSA 10 is worth more, roughly $336 by our estimate, and a PSA 9 around $118.
It is a Rare, and it shows up about once every 32 Mysterious Treasures packs.
Mitsuhiro Arita drew the art for this card.
Yes, as a digital simulator. Holobrook lets you open Mysterious Treasures booster packs in your browser with the set's real pull rates and keep what you pull in a digital binder. No real cards, nothing to buy.