Be terrified by the horrible Growch! Visit GROWCH to cower in his shadow (Can also be found on Growch1, Growch2, Growch3, etc... similarly to Growganoth).
This is a special WinterFest feature only available during the last week of December (December 18th through the 31st).
The Growch has a teeny tiny black heart. He hates giving, kindness and holiday cheer! But maybe, if we all give him Winter Gifts... he'll learn what the holidays are all about. Plus, he might give us some stuff, so rock on.
This is global team effort to unlock new WinterFest Items. The goal is to level up the Growch's heart by giving him Winter Gifts. Once he is happy enough, his heart will grow, new items will be unlocked, and you will no longer be able to give him gifts for some amount of time.
If you try giving him Winter Gifts while he is leaping for joy, he will happily decline the offer and return the Winter Gift to you.