Cocoon (1985)

A group of aliens return to earth to retrieve cocoons containing the people they'd left behind from an earlier trip. These cocoons had been resting at the bottom of the ocean. Once retrieved, they stored these recovered cocoons in the swimming pool of a house they'd rented in a small Florida town. Their mission is hampered by a number of elderly people from a nearby retirement community who had been secretly using the pool, and who discover unusual powers from within these cocoons.