They were left out in the sun (or in a window) for an extended period of time and allowed to fade
There are two primary ways to deal with a creature: blocking in combat and casting removal
Usually, Jin-Gitaxias, Core Augur is found in decks that reanimate creatures because its difficult to cast this card for its full cost and might not even be worth it
However, since paid players progress much faster, they have a better chance of accessing strong cards like the EX versions of top Pokemon, which can impact the metagame
As with most Hardened Scales decks, games with your namesake card feel much easier and this decks resurgence during the Hogaak era was partly due to the London Mulligan making those games more likely
It was fun, but it felt less Dragony than Id want with the progenitor of all Dragons as your Commander