  Recently an intriguing transient AT 2018lqh, with only a day-scale duration
and a high luminosity of $7\times 10^{42}\ {\rm erg\ s^{-1}}$, has been
discovered. While several possibilities are raised on its origin, the nature of
this transient is yet to be unveiled. We propose that a black hole (BH) with
$\sim 30\, M_\odot$ forming from a rotating blue supergiant can generate a
transient like AT 2018lqh. We find that this scenario can consistently explain
the optical/UV emission and the tentative late-time X-ray detection, as well as
the radio upper limits. If super-Eddington accretion onto the nascent BH powers
the X-ray emission, continued X-ray observations may be able to test the
presence of an accretion disk around the BH.
