Animals and fungi predominantly use two different modes of cell division — called open and closed mitosis, respectively. A new study has shown that different species of Ichthyosporea — marine protists that are close relatives of both animals and fungi — use either open and closed mitosis, closely correlated to whether the species has multinucleate life cycle stages. The study demonstrates the way animals do cell division might have evolved long before animals themselves did and how this is linked to an organism’s life cycle.