Some trippy stuff. The ending is a bit dark, but at least we know that Daughter is a selfless individual, right?
As for what happens to the dog, well, since everything is pretty much eliminated once it serves its purpose (Woman, the Droid) then we can safely assume the same happened to the puppy…sad. I know.
Stream I Am Mother on Netflix now.
Source : https://www.distractify.com/p/i-am-mother-ending-explained