If you sit down next to a cat, and throw your arm over the back of the sofa while someone reaches over from behind and starts to pet the cat, and then after a little bit you stand up and leave while the phantom arm is still petting the cat, the cat understands that something really freaky is happening, gets scared, and runs away.
I would have thought they’d be happy that whatever weird thing is happening is petting them, but apparently not. An arm with no human is alarming and bad. I think it’s cool that their mental model is that similar to ours.
Mammals in general are so smart that I wonder if this mental model is shared by the whole class, or at least the Boreoeutheria (clade that includes both carnivores and primates, plus a lot more critters). And, like, the evolutionary benefits of that model are obvious - if whatever tore your arm apart is still lying around, you need to run away ASAP.