Slow moving object changing colors, then in a matter of seconds, was back where it started and descended slowly behind the tree line.

I have never reported this to anyone but it has been on my mind since the incident.
It was all Hallows eve, I know this because we were out teepee-ing (w/rolls of toilet paper) people.  We were on Curtis Rd in Hope Michigan sitting in a field waiting for someone to turn their porch light off so we could teepee them.
As we waited, I watched the night sky and noticed a red light.  I didn't think much about it at first because it looked like a plane.  After about 5 minutes, I looked again and it was green.  I pointed it out to my brother and cousin who were with me and we all watched as it went straight across the sky continually changing colors.  It took a good 15 minutes to travel the distance it would have taken a plane only 3 or 4 mins.  About every minute it would change color, many colors.  Red, green, blue, yellow, orange.
We kept watching and was getting ready to give up on these people going to bed but just before we got up it stopped, and in the matter of just a few seconds it was right back to where I first saw it.  It then started to drop slowly down until it was behind the tree line and disappeared.
To this day I do not know what it was, it made no sound, but I'll always remember the date.  The area where I believe it was going down has been known for other ufo sightings as well.