  KT Mon has been considered as a classical nova in 1942 based on its light
curve and spectroscopy. However, we noticed a unusual feature for a nova soon
after its maximum: the early presence of high excitation emission lines such as
He II and N III. We propose previously overlooked interpretations that KT Mon
can be either a WZ Sge-type dwarf nova and an X-ray transient, although the
possibility of an unusual or a recurrent nova is not completely excluded. If KT
Mon is a WZ Sge-type dwarf nova, the system is expected to have a brown dwarf
secondary. If KT Mon is an X-ray transient, the system is a good candidate for
the nearest black-hole binary. Within our knowledge, the observed features seem
to more strongly support the latter possibility. In all possibilities, we can
expect a recurrent outburst in meaningfully near future.
