Multiple lights that contracted then retracted into one then disappeared.

At about 9:00pm on May 4th, my boyfriend and I decided to walk to the store.  While walking I happened to look up and we saw about 15 or so lights that were in a straight line contracting moving away from each other then shortly after retracted and disappeared.   They stayed in a straight line and the best way of describing it was like a coil or slinky being stretched.  As the line formation contracted the lights grew further apart yet held in line formation and at the end before disappearing they retracted coming back together as one and then disappeared.  Both of us tried taking video and pictures with our phones and were both strangely unable to as both froze...  Strangest yet most intriguing thing I’ve ever seen!