Kubfu is Legendary Pokémon which has been the special reward of the Advent Calendar 2022.
If you opend at least 20 doors you were able to recive this Legendary. If you were able to open all 24 doors, you were also able to recive one of the evolution items.
Kubfu had a comeback through an Event Destribution on 2024 January 1st to 18th. Since then the evolution items can rarely be found during rumbling the Galar Area.
"The legendary Fighting Pokémon Kubfu is back with an increased shiny chance! Collect Event Points to receive this exclusive egg."