What does "that thing" refer to?
You can see in the clip that Grizz is pointing at the puppy sleeping nearby. So "that thing" refers to the puppy. The phrase "that thing" was probably chosen to emphasize that Grizz does not think the puppy is that great and therefore won't even bother to call it by its proper name. This is a common way of using "that thing" in English. It is often used to show dislike or even disgust toward something. Ex: Gross. What is that thing? Ex: You don't expect us to eat that thing, do you? Ex: I can't wear that thing. It's hideous!