Probability mass functions tracing the environmental density distribution of luminous galaxies at Alcyoneus’s redshift. Like most galaxies of similar r-band luminosity density and redshift, Alcyoneus’s host has no galactic neighbours in SDSS DR7 within 5 Mpc. However, within 10 Mpc, Alcyoneus’s host has more neighbours than most similar galaxies. For all 9358 SDSS DR7 galaxies with an r-band luminosity density between 75% and 125% that of Alcyoneus’s host and a co-moving radial distance that differs by at most r₀ = 25 Mpc from that of Alcyoneus, we count the number of SDSS DR7 galaxies, N_{< R}(R), within a sphere of co-moving radius R = 5 Mpc (top panel) and R = 10 Mpc (bottom panel). The top panel indicates that Alcyoneus does not inhabit a galaxy cluster; the bottom panel indicates that Alcyoneus does not inhabit a void.