What do you all believe in?
I know at least two friends who were the victims of possession. Both were highly educated, from educated families. We called police and paramedics on one. They sent her to mental care and gave her the drugs needed, but the screeching and demonic voice still remained. Both were cured permanently when an exorcist came in.
Both friends said their bodies were out of their control and even surprised when they started talking to the exorcists. One had a very mother who was a highly educated medical doctor. She was the victim of such a thing in the past and paid a lot of money to fly in the exorcist.
A relative was sick for a week. She went to a high end hospital, ended up in intensive care, attended to by specialists. Treatment cost $3,000, and the hospital finally released her because they did everything they could and the insurance wouldn't let her stay much longer. Another relative offered a spiritual treatment and her fever cooled within an hour.
Now you can call all these things coincidental, but the correlation seems very strong, whether exorcism is a first or last resort.
They seem a lot more dangerous in jungles, or areas that were cleared out from a former jungle or swamp. So I'm inclined to think they live like wild animals rather than being the residue of dead people.
My girlfriend had an "anger-attack" that you really cannot authentically describe without using the word possession. It was absolute madness. Cursing, highly aggressive, would not stop even when she slit her hand on a shard of glass and fell face first to the ground busting her lip. She did not feel anything. I was looking her in the eyes and it was not the same person. Her gaze was changed.
Now, you can explain all this away and say it was a chemical imbalance in her brain, psychological trauma, etc.. But really all these explanations just feel like approximations to what it really felt like. It felt like a demonic possession. I know it sounds silly. I am a very scientific/skeptical guy myself but this was something else.
The big difference is we have seen sharks, we have seen orcas, and it makes a lot of sense for an orca to want to eat a shark. But ghosts seem to make less sense and there is no clear source.
We have no evidence that humans have pooped on the moon. But the people claiming so are credible. The people claiming ghost sightings are much less credible and often in the group that believes other mystic things.
There are some dedicated ghost hunters, but they are as credible as the Mythbusters, at best. Ghost hunting requires expensive equipment and possibly some scientific training. It's likely to be a career dead end - you can't go from being a ghost hunter to being a physicist. And very few would want to fund it.