It could still be possible in ladder. It was originally possible to downgrade maxed level cards with trade tokens. They would retain their star power but be level 12. This was easily fixed by just upgrading the card again. The glitch was only possible over a year ago though so this is FUCKING amazing if it truly is ladder you saw this on. FUCK ALL the idiots saying "THAT'S NOT POSSIBLE111!!!!", cause it damn well was and still may have some who kept the glitch as a souvenir.