My friend and I were walking a trail along the St. Joseph River and decided to step off into the woods to smoke a blunt. We were there for a while in silence but as the sun started setting, we began to hear what sounded like a pan flute playing the same, short rhythmic tune repeatedly. We assumed it was someone in the neighborhood nearby at first but it started to seem more supernatural as time went on. The flute didn't stop , even for a second, for the next two hours. We began to head back the way we came and for over a mile... the sound followed us. It also never got louder or quieter and there was never even a pause or irregularity in the pattern. We shined out flashlights around, made ridiculously loud noises, ran, and did anything we could but it never altered the flute sound in anyway nor did we see anything. When we left the woods, the sound still followed until we got into the car. I haven't heard the sound again but since then anyone I bring on the trail with me says they feel like they are being watched which never happened before this.