The Hero's Costume is a Gamepass in Adopt Me! released on April 11, 2020, which was also the day when the Dress Your Pets update was released. This Gamepass contains three pet accessories:
The Hero's Costume cannot always be bought as it is on rotation with the Pirate's Costume and Royal Butterfly Bundle. It is not shown in the Shop GUI either.
The Hero’s Costume is displayed on an Arctic Fox in the image of the Gamepass. However, in-game before buying it at the Hat Shop, it is shown on a Dog.