On October 27, 1954, play stopped at Florence's Artemio Franchi stadium as formations of silvery objects passed overhead, witnessed by approximately 10,000 spectators, players, and referee. Silvery filaments fell from the objects; samples collected by a University of Florence student were analyzed and found to contain boron, silicon, calcium, and magnesium, not spider silk.

Giorgio Batini, editor of La Nazione, and colleagues climbed to the newspaper's roof and independently confirmed the aerial objects. The analysis by Professor Giovanni Canneri at the university's Institute of Chemical Analysis found the fibrous material had a composition inconsistent with any known natural biological source. The same phenomenon was reported across northern Italy and eastern France throughout October 1954.