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On 2022 September 8 comma Pan-STARRS detected a dust tail - trail associated with a new main-belt asteroid candidate. Confirming follow-up observations with the 3.6m Canada-France-Hawaii Telescope on September 22 show a tail corresponding to at least 25 comma 000 km length in space. A search of the Pan-STARRS image archive shows no matching object in pre-discovery images comma nor could the recent astrometry be linked to any existing asteroid comma or isolated tracklets comma implying that this is a new discovery that was not previously visible. Something happened recently to trigger significant activity comma resulting in an increase in brightness by at least 2 orders of magnitude. We propose a DD programme of WFC3 imaging over two orbits. Only HST will allow us to study the changing morphology of the dust structures and thus differentiate between continuous mass-loss and an impulsive event.