Pokemon Go Yamask Removed from the Spawn Pool, it was Intended to be a Spawn Exclusive
Better Luck Next Year to Everyone who Failed to Catch a Shiny Yamask

Trainers, Yamask can no longer be encountered in the game and according to Niantic, Yamask was meant to be an exclusive Halloween event spawn. So, if you have wondered where are the Yamask spawns, here is the answer.
The Gen 5 Ghost Type Pokemon Yamask made its debut in Pokemon Go on October 17, when the Halloween Event started. During the event, Yamask was available via Field Research reward, in 5KM Eggs, as a Tier 2 Raid Boss and in the wild. They also released Yamask’s shiny form.
After the Halloween event came to an end, Yamask ‘disappeared’ from the game and players started to wonder what happened with Yamask and why it’s removed from the spawn pool. Well, things were not clear until today and Niantic confirmed that it was meant to be a spawn exclusive.
Here is their explanation:
Hi, I can confirm that Yamask* can no longer be encountered in the wild. It was intended to be a spawn exclusive to our Halloween event, and we apologize that we didn’t communicate this better.
Now, this got a lot of players angry, as they didn’t catch the shiny form, because no one explained that Yamask + shiny form will be a Halloween event exclusive spawn.
What is even more interesting is the fact they already announced 4 four costumes shiny Pokemon that were an exclusive spawn and made Yamask exclusive spawn too.
To be honest, if I, and I guess if many of you knew ahead of time that Shiny Yamask is an exclusive spawn, we would have to try harder to catch the shiny form, which is now gone forever.
Not cool Niantic, not cool!
…I remember them saying that Yamask was a spawn exclusive for the Halloween event… seemed obvious but I guess not.
Oh, so sad for you…
It looked like a Halloween Type to me. Such a no brainer… Why does one have to explain everything nowadays to not anger people? Be happy you got to catch it for Halloween. I bet we’ll see it again next Halloween. So stop whining… 😀
Hopefully they will do another event this Halloween. My son is just now getting old enough to get into Pokémon and he is obsessed with Cofagrigus since we read about him in a book.
Guess I was lucky to get the couple I got. Shame I transfered all but one. Oops. I’m sure it’ll be back someday. I keep thinking I missed too many legendaries to make it up then they do events and raids and boom I have most of what I missed in 3 years. ♂️
It’s not gone “forever”, and there was no reason to think it would be. “Halloween exclusive” doesn’t mean “Halloween 2019 exclusive”. Over-dramatic article.