Unseen Entity?

This is my first post. This literally just happened less than an hour ago.

This morning, I let my dog inside. So, for awhile now, she would concentrate down the hallway, or near the hallway as if someone was there. Once I started reading these stories, I realized that there may be a spirit. She always had that: "Holy crap!" look on her face.

One night, she was staring into my sister's room with that look on her face, so I moved up right next to her and stared into the room. My facial expression was pure anger because my intention was to protect my dog in case the spirit was harmful. My dog walked into the hallway as if she was following something and then stood there for a second, and turned around and came back into my parents' room. She repeated this a couple times. She eventually backed off and took position to my left. I continued staring into my Sister's room with the same facial expression. And my dog was looking at me with her head low, giving me that: "You saw it too!?" look. I basically attempted to comfort her.

Now for what happened today...

So, my dog was lying down in front of me, I'm sitting on a couch right now in my living room. She was lying down in front of me and to my right. Suddenly, she jumped and gave a shocked look towards the hallway. I immediately gave my angered look and stuck up my middle finger in the general direction and said: "Don't scare my dog."

Before that, she was doing that typical stare towards the hallway, with that: "Oh my God..." look. I was going to get my coffee, so I flicked out a knife and approached the kitchen cautiously, because it's right there by the hall.

I've always felt safer when I had a weapon in my hand. It comforted me. I've responded to my Dog concentrating on this entity with some hostility. I'll taunt it and I generally am armed with a knife, at least, so when my dog stares down the hall, I either pull out a knife, or, if I'm training with my sword, I'll have that... When I'm unarmed, I'll get in a boxing stance. Either way, no matter what, I do a slow advance towards the hallway. Sometimes I advance into the hallway.

Once I do that, the entity vanishes, I guess, because my dog basically stops reacting to it and carries on.

I guess that's all it takes to maintain the peace, so I'll keep reacting that way. But I would like to know the intentions of this spirit, or if my dog is just crazy and thinks there's a spirit when there's really nothing. I haven't seen anything at all. I don't feel anything, hear, smell, nothing changes.

I have a lot of theories. It could be a residual haunting, or entirely in my dog's mind.

But I would like to talk to this entity and know its intentions, what it wants, and why it's here. No physical harm has been done, and my dog doesn't appear to be hostile towards it. I don't really know what to believe at this point.

If it was evil, it would've done something by now. If it was good, then why startle/scare my dog?

Any help/feedback would be greatly appreciated! Thank you in advance!