<human>: Can you succinctly summarize the text in 1-3 sentences?

Just curious. For me, its a story from my Grandma that happened to her and my now-dead Grandfather.
He was an Anglican priest, and im not Religious and regard it as plausible but whatever, irrelevant. 
One night these teenage kids came into the Church (they lived out the back at the time) and were raving about how they'd been playing with a Ouija board (story is also why I dont want to ever touch one) that night.
Anyway one their friends had become "Possessed" and was barking, talking with a demonic voice and being relatively horrifying. My Grandma didn't give me many details and I have yet to ask my Uncle who was present but they essentially did an exorcism/cleansing of some kind to this kid.
Whether it was due to psychological problems or he was really possessed, its still creepy purely because it happened to people so close to me.
<bot>: Grandfather performs exorcism on teenage kid that had been playing with Ouija board. What's Reddits paranormal story?