A little extreme.

I don't believe a ghost could actually kill anyone (unless maybe someone had a heart attack from fright!)
Keeping an open mind doesn't mean letting the imagination go insane. A healthy balance should be kept between the scientific & the spiritual.
I can't honestly say I believe in ghosts because I've never actually seen one (except possibly here). Altho, I have known a lot of other rational people who believe they have seen one.
Myself, I happen to know there is some kind of existence after death. I say I know (not just merely believe) because I have had many communications of this kind. No visual "ghosts"...but communications in several different ways (as varied as the person who passed) shortly after the person died. Oftentimes there have been messages that I've passed on...& always the message was legit & there was confirmation it was real.
A lot of ghost "sightings" I've heard about have been from people who say they saw loved ones shortly after they passed. So, when someone has had such experiences, it's not a hard stretch to imagine such a thing as ghosts exist. The difference there would be if it was possible for a spirit to hang around for a lengthy time after passing over. Do they? Who knows. But ghost sightings have been going on for centuries.
And...it might be possible that a spirit would "use" the life energy from surrounding living things...like a tree...to manifest an image of themselves.
In this case, I had been observing this house for several days from a few different perspectives. Gorgeous house with very interesting architecture. Then, I actually went over & into its courtyard to take a close picture. This was the only house I photographed where I had spent a lot of time observing it beforehand. And it was the only house where something like these appeared. (After this, I went thru all others with a fine-toothed comb!) Perhaps I myself was observed while I was observing...& the observers found a way to let me know.
Not so crazy. I think it's a fascinating possibility.
And...who doesn't love a good ghost story?
O, BTW---I'm quite skeptical when it comes to "orbs". You never heard about them 30 years ago, but only recently. At least, I never heard of them.
“I am innocent. I leave it to my counsel to speak for me.”
—Lizzie A. Borden, June 20, 1893