Body swap and possesion ring

Recently, I was walking in the park late at night. I bumped into stranger and something fell out of his pocket. It hit the ground with a resounding thud and flashed. I picked it up. It was a ring. It was gold and had a rather large red stone on it. I turned around and looked to see how far this passerby had gone. I couldn't see him in the dark, so I shouted, " Hey, mister! You've lost your ring!" He didn't respond. I stood waiting for him for a while, then put the ring in my jacket pocket and continued walking, forgetting about it.

After a while, I returned home and took the ring to my room to examine it. It was engraved with the "Body Swap and Possession Ring". I looked at it for some time, but found nothing but the inscription. Then I put it on the nightstand next to my bed, changed my clothes, and went to bed.