Kerrison et al. report the discovery of an intervening neutral hydrogen (HI) 21 cm absorption line at a redshift of z = 0.88 towards the z = 1.284 quasar PKS 0405−385, identified in ASKAP FLASH (First Large Absorption Survey in HI) observations. In the 1990s, this quasar displayed the then most rapid known intraday variability at radio frequencies, from which it earned the title of “the smallest radio quasar”. Although its size was revised upwards soon after based on updated scattering theory, PKS 0405−385 remains an important probe of Galactic plasma, and now also of intervening gas discovered through HI absorption. The figure above shows the ASKAP spectrum of the intervening HI lines towards PKS 0405−385. The velocity scale is relative to the systemic redshift of z = 0.88. The y-axis indicates the absorption strength as a fraction of the continuum flux density. The grey band indicates 5× the per-channel noise, taken from a blank sky spectrum around the target.