Havak
Pokemon master
Yeah, it's a really annoying part of the game thoughI feel like 5k are always trash once you've been playing long enough. I only incubate them to get rid of them and increase my chances of getting more 10k's.

I would be so happy just to hatch a single Vulpix, Growlithe, Machop, or Grimer as that would put me very close to getting their final evolution, but it never seems to happen. I've never looked up the chances, but they must be far rarer.
2km and 10km seem to be much harder to come by at the moment as well, I'd wager that my last 30~ eggs have only included about three 2km and two 10km.
Is Grimer like one of the hardest Pokemon to catch and/or hatch?.
Feels like they are impossible to find in London anyway.
Yeah, I remember reading an article when it was double Candy for Buddy's. Grimer was stated as one of the better picks as for some reason it's very rare in most parts of the world.