It’s an animal, a squirrel or mouse or something scurrying around. It’s not a ghost, ghosts do not exist according to many scientific studies and analysis done.
Occam’s Razor, often summarized as all things being equal, the simplest solution is the best, applies in this situation where we are looking at a dog’s behavior of growling, staring up at, and chasing an unknown object in the ceiling. These behaviors are indicative of a dog hunting or tracking something, that’s for sure. The question is, is it a ghost, or is it a critter. A critter is the easiest answer, as there are lots of little animals who take shelter in the cold months, and houses often have holes where a mouse or squirrel can get in. As well, there are known solutions for getting rid of critters, such as setting traps and examining your house for entrance holes. Since ghosts have not been proven to exist by science, there’s no sure-fire “ghost-be-gone” spray or method to get rid of one, so I argue it would be more beneficial to look into solving the critter problem than to keep believing it is a ghost.