Demon Core is an immersive sound and light installation which explores the concept that energy lies within the heart of all matter. The work is darkly inspired by an incident that happened at the Los Alamos nuclear laboratory in 1946 when an experimental plutonium orb accidentally went supercritical causing a fatal nuclear chain reaction. The plutonium orb was thereafter known as the “Demon Core”. Demon Core was exhibited at DARK MOFO 2019, and housed in the Queen Victoria Powder Magazine in Hobart. An experimental interface between humanity and the fundamental yet fearsome forces of nature, the installation contains scientific instrument assemblages, a spherical sound sculpture, and radioactive materials, which are used to trigger pulses of light and sound. A sample of uranium ore activates the installation via a custom-constructed Geiger counter assembly. This triggered fluorescent cymatics activated by UV lighting, and spatialised sounds created with a custom-built rackmount analogue sound synthesizer and a 24-channel custom-made immersive sound system.