To welcome the upcoming OVA featuring Anehata Shiton that will come bundled with Golden Kamuy volume 23, a minigame was made available from 29 June to 14 July 2020 on the official website.
You shall start here, where you will see seven spaces for stamps, with inside each a hint for an animal and where you can find it. You must find at least four of the seven animals hidden on various pages of the website to unlock special icons and a wallpaper made by Irasutoya. Every time you find one, click or tap on it. You will be prompted back to the special game page, and you will see the stamp that corresponds with the animal you have found appearing in the respective space.