A radiolarian is a single cell that secretes a mineral cathedral around itself. Radiolaria Serena renders that skeleton at human scale in transparent polymer and light: a slow, continuous plasma that breathes through the lattice, the organism at rest. The light gives the microscopic architecture something it never had: visible emotion, here in its calmest state. The work is the current centre of a series begun in 2020 devoted to these unseen marine architectures.