Since Kamala Harris was widely seen as besting him at the debate, Donald Trump has spread conspiracies and spun false tales, losing focus on what polls say matters most to voters.
Trump is the Crystal Pepsi of politics. Basically poison, crushed-up bugs and baby oil flavored sugar water. Totally transparent, and dragging down the brand.
Hell, even Tab Clear was better. Source: the cafeteria at my high school stocked both back in the day. They were both bad
His brain is like mashed potatoes at this point, almost everything he regurgitates is something his staff prints out for him every morning (how he gets his "news"), TV, or some wild troll farm coming to his social feed. He then sees these things and runs with them because he has no critical thinking skills at all. That is why his handlers try and talk to him through the TV appearances and op eds that could be printed for him.
The pets stuff was from Fox and others knowing it wasn't legit but putting it out for Trump to pickup, though probably for his rallies, as at the debate it did not land.