  K2 observations of the weak-lined T Tauri binary V928 Tau A+B show the
detection of a single, asymmetric eclipse which may be due to a previously
unknown substellar companion eclipsing one component of the binary with an
orbital period $>$ 66 days. Over an interval of about 9 hours, one component of
the binary dims by around 60%, returning to its normal brightness about 5 hours
later. From modeling of the eclipse shape we find evidence that the eclipsing
companion may be surrounded by a disk or a vast ring system. The modeled disk
has a radius of $0.9923\,\pm\,0.0005\,R_*$, with an inclination of
$56.78\,\pm\, 0.03^\circ$, a tilt of $41.22\,\pm\,0.05^\circ$, an impact
parameter of $-0.2506\,\pm\,0.0002\,R_*$ and an opacity of 1.00. The occulting
disk must also move at a transverse velocity of
$6.637\,\pm\,0.002\,R_*\,\mathrm{day}^{-1}$, which depending on whether it
orbits V928 Tau A or B, corresponds to approximately 73.53 or 69.26 $\mathrm{km
s}^{-1}$. A search in ground based archival data reveals additional dimming
events, some of which suggest periodicity, but no unambiguous period associated
with the eclipse observed by K2. We present a new epoch of astrometry which is
used to further refine the orbit of the binary, presenting a new lower bound of
67 years, and constraints on the possible orbital periods of the eclipsing
companion. The binary is also separated by 18" ($\sim$2250 au) from the lower
mass CFHT-BD-Tau 7, which is likely associated with V928 Tau A+B. We also
present new high dispersion optical spectroscopy that we use to characterize
the unresolved stellar binary.
