J.R.C. thanks B. Gaensler and S. Farrell for conceiving the radio and X-ray survey that led to the discovery of Apep. We also thank N. Smith, K. Valenta and O. de Marco for discussions in the early stages of this study and A. Cheetham for help in constructing the NACO and VISIR observing schedules. We thank R. Lau for reviewing our manuscript and providing insightful comments that lead to important improvements in the manuscript. P.G.T. and B.J.S.P. are grateful for funding from the Breakthrough Prize Foundation. This work was performed in part under contract with the Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. B.J.S.P. is a NASA Sagan Fellow. P.M.W. is grateful to the Institute for Astronomy for continued hospitality and access to the facilities of the Royal Observatory, Edinburgh. We acknowledge the Gadigal clan of the Eora nation, the traditional owners of the land on which the University of Sydney is built, and we pay our respects to their knowledge, and their elders past, present and future. We also thank Y. Han and J. Prenzler. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France, and NASA’s Astrophysics Data System. The results presented in this Letter are based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 097.C-0679(A), 097.C-0679(B), 299.C-5032(A) and 299.C-5032(B). The Australia Telescope Compact Array is part of the Australia Telescope National Facility that is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. The scientific results reported in this article are based in part on data acquired through the Australian Astronomical Observatory, on data obtained from the Chandra Data Archive, and observations obtained with XMM-Newton, an European Space Agency (ESA) science mission with instruments and contributions directly funded by ESA Member States and NASA.