The first big event for Pokémon Go 2021 will be the Unova Celebration event. It starts on January 5 at 10 AM and goes until January 10 at 8 PM in your local time zone. Several notable Unova Pokémon will be appearing throughout the event for players to capture and add to their collection, with new appearances, such as a shiny Snivy and a five-star raid featuring Genesect with burn drive installed.
The Unova Celebration is also the first time collection challenges will be happening where players must capture specific Pokémon appearing in the event. Doing so gives you a few rewards and a badge showing the date and time you complete the event. One of the Pokémon you need to catch for the Unova Collection Challenge is Lillipup, and another one is Herdier, which is Lillipup’s second evolution. You might be thinking you can catch a Lillipup for the event and then evolve it into a Herdier for it to count.
That’s not the case. If you catch a Lillipup while the collection challenge is live, that counters, but evolving it into Herdier does not. You will need to encounter a Herdier in the wild or a raid and then capture it, just like you did Lillipup. Players who gained access to the challenge a bit earlier than everyone else due to an error on Niantic’s part have tried this method with no success.
If you’re having trouble encountering a Herdier, it should be available to spawn in the wild or in a three-star raid. Both are fairly simple methods to capture this Pokémon, so it’s not too complicated. The big question will be how long it takes trainers to capture all of the Pokémon to see who can do it the fastest.