Theories range from lanterns, nighttime skydivers or LED lights tied to drones. Some even think they may have been visitors from outer space.
It turns out, they were balloons launched from an annual Queen Creek church event, with LED lights fastened to them.
Steven Lowder, Second Councilor at the Church of Jesus Christ of Latter-Day Saints in Gilbert, said it's part of a yearly tradition the church has done now for the last five years.
"One of the things that we do maybe quite unique to our mission, is to remember friends of ours who've made their first covenants with Jesus Christ," said Lowder. "We tie a little LED light to a balloon, one for each person who was baptized, and we take that out to the field at night and let that go just as a part of a celebration. Each balloon represents one person, one of our friends who's made a covenant with Jesus Christ through baptism, to grow closer to him, and to be like He is."