Not saying that this is what you saw, but there’s a very interesting “mirage” phenomenon called a ‘fata morgana’ - has to do with the way light bends through layers of air of different temps:
https://en.wikipedia.org/wiki/Fata_Morgana_(mirage)#Observing_a_Fata_Morgana
Yup, when I was twelve, my Mom and I saw an island in the shy, complete with Palm Tree.