Glowing object zigzagging dropping glowing balls through sky witnessed by multiple people on highway and by law enforcement.

My boyfriend at the time and I, with his friend, and girlfriend--four of us were driving at night to go swimming at Sand Pit Road--a popular spot for many to swim at night and a boat landing.
It was very hot that day--we were going to cool off.
I am uncertain of exact month/date, but it was hot, and we were traveling from Omro on Highway 21 towards Oshkosh, when we saw something that looked like a light zig zagging fast across the sky.  It would be in one spot, and seconds another, and glowing colored fireballs were coming off it.  It was moving almost faster than our eyes could track.
We slowed on the highway as other cars were too.  We could see other people watching.  We know what we saw.
We continued to the spot to swim, but also with the idea that maybe we could see more from the edge of the water across a clear sky.
We were not the only ones with this idea.
There were multiple emergency vehicles there (at the end of Sand Pit Road next to the boat dock parked).  We were afraid to get out of our vehicle.
I got out of the car while my friends remained inside.
I approached one of the officers who was watching the sky and what we were seeing as well (there were several law enforcement vehicles parked with officers and responders watching) and I asked him what it was.
He replied, “I do not know.”  Everyone was silent.
After the object disappeared, all of the emergency vehicles left quietly and we decided not to swim, and we never went back to Sand pit Road to swim after that.