That may be the point is to muddle the perspectives. What's interesting to me though, is that both the dad and dog have a different perspective from Miko, despite also being spirits. I'd have thought they'd have a more clear picture on what they're dealing with, rather than carrying the same cryptic perspective from their former mortal life. Much like how the little girl at the hospital viewed the ghost with the wheel chair differently as it carried their family into the afterlife. 

My assumption is that this either this is their concept of Death, or something like it. Could even be an enemy of Death itself, if even spirits have a problem with its presence. Unfortunately, since there's no actual information about it, beyond it being a threat, it's a bit difficult to glean anything from this chapter that technically wasn't already established.

what we see here*

Not noticing an edit button, which is a pain.

I would assume the cat turned into the dog spirit. Either that, or a dog ate the cat and the dog died.

The biggest thing about this is that this is specifically her depiction of the spirit. So it could actually be a cat spirit, but to her it's the dog.