More info! And the patreon description for it:

Someone found a big fungus colony (well, big for what it is, they're usually the size of a grape and eat bugs and decaying things), and they kept it and fed it. Once it started growing they put it into bigger toys so it'd feel it had a shell to hide in, and after a while it started to use the toy arms and legs to push itself around, and over a few more years it learned to balance itself enough to stand! Eventually the person started to put it into doll bodies so it could learn to use hands, and he taught himself how to make dolls so that he could make better fitting bodies for it. It grew smart enough that it could interact with him and use it's hands to tell him what it'd want, and over the years he learned and taught Gabi some sign language and made bodies that had fingers so that it could sign more specific things. Near the end of his life Gabi could form simple sentences, so it could help him around the house and do some of the chores that he couldn't anymore. Now that he's gone Gabi is intelligent enough that it misses him, and is sad about it, but continues to keep the house clean and maintain itself, having learned to sew and clean itself from him, and feeding on animals and some plants in the woods around the house.

It may look freaky, but after just 10 years or so of being around him it'd act like a small dog, liking the feeling of safety and curling up on him to sleep or get attention. After it was 30 years old it'd probably act like an infant, following him around or wanting to be held and fed. Now at over 50 years it likes interaction and being told stories, or easy games like checkers or building blocks. It still can't understand very complex things, but it likes to be talked to and will ask things about the story that it can understand, and it'll probably lose at checkers every time, but it still thinks it's fun because it's something it can play with humans.