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We report the discovery of a new ``changing-look'' active galactic nucleus(CLAGN) event, in the quasar SDSS J162829.17+432948.5 at z=0.2603, identifiedthrough repeat spectroscopy from the fifth Sloan Digital Sky Survey (SDSS-V).Optical photometry taken during 2020--2021 shows a dramatic dimming of${\Delta}$g${\approx}$1 mag, followed by a rapid recovery on a timescale ofseveral months, with the ${\lesssim}$2 month period of rebrightening capturedin new SDSS-V and Las Cumbres Observatory spectroscopy. This is one of thefastest CLAGN transitions observed to date. Archival observations suggest thatthe object experienced a much more gradual dimming over the period of2011--2013. Our spectroscopy shows that the photometric changes wereaccompanied by dramatic variations in the quasar-like continuum and broad-lineemission. The excellent agreement between the pre- and postdip photometric andspectroscopic appearances of the source, as well as the fact that the dimmestspectra can be reproduced by applying a single extinction law to the brighterspectral states, favor a variable line-of-sight obscuration as the driver ofthe observed transitions. Such an interpretation faces several theoreticalchallenges, and thus an alternative accretion-driven scenario cannot beexcluded. The recent events observed in this quasar highlight the importance ofspectroscopic monitoring of large active galactic nucleus samples onweeks-to-months timescales, which the SDSS-V is designed to achieve.

A Transient "Changing-look'' Active Galactic Nucleus Resolved on Month Timescales from First-year Sloan Digital Sky Survey V Data