Exactly what it says on the (dramatic) title.
We always hear about Biblically accurate angels: the burning wheels with tons of eyes, the strange looking creatures that sound like they come from the anime “Evangelion”, the cherubim with 4 faces, but I had a thought while watching The Exorcist: Believer (it was…not good for anyone wondering. At all. The disrespect Regan’s mom had towards Merrin and Karras after they died saving her daughter was baffling to listen to, especially…but i digress) a couple of days ago, specifically, if that’s how the demonically possessed are said to more or less act in the Judeo-Christian scriptures, or if they’re they completely different to what we see in movies and games. I’m guessing it’s more than likely the second one, right, but I’m curious about the details like the signs someone’s possessed, the demon’s endgoal, and what they look like, basically everything you can gimme to sate this curiosity or to send me on a rabbit hole, if you’d be so kind?
Surprisingly, a lot of the creepy media is fairly accurate, though extreme. Demons aren’t prominent, we know they are angels who rebelled with Lucifer, and were cast out, so that would be their appearance, but in reference to possession, we basically have those that Jesus encountered and a few his apostles drove out in his name later on.
And what we see are people behaving almost like animals, screaming, shouting, with an inhuman strength to break chains or whatever locals have tried to contain them with, and inflicting a lot of self harm. There’s a woman who would throw herself into fires, a man who had 100 demons in him (where “I am legion” comes from") who would throw himself onto rocks and off cliffs and cut himself, etc.
The more manufactured elements are the head twisting, anything to do with pentagrams, and honestly a lot of the hostility to others. People usually steered clear, but demon possessed individuals generally did more self harm than harming others, with cases where Jesus would meet them within cities, and they weren’t surrounded by dead people or a panicking mob or anything. They also don’t “haunt” or hunt people like they do in movies, but are usually extremely obvious.
Anyway, that’s my experience purely from biblical account, off the top of my head, I’m sure others can add more detail or examples.