In the context of the Backrooms, which is a fictional and eerie setting often explored in internet creepypasta and urban legend narratives, the appearance of a dog in Level 0 could be considered unusual. Level 0 is typically characterized as an endless expanse of monotonous, dimly lit hallways and empty rooms, devoid of natural life. Encountering a dog there could evoke feelings of confusion and intrigue, since animals are generally not mentioned as inhabitants of this unsettling environment.
If the dog appears calm or friendly, it might lead to questions about its origin and purpose in such a surreal and creepy place. Alternatively, if the dog behaves erratically or in a supernatural manner, it could heighten the sense of unease that the Backrooms inherently convey.