  We present the discovery of DELVE 6, an ultra-faint stellar system identified
in the second data release of the DECam Local Volume Exploration (DELVE)
survey. Based on a maximum-likelihood fit to its structure and stellar
population, we find that DELVE 6 is an old ($\tau > 9.8$ Gyr, at 95%
confidence) and metal-poor ($\rm [Fe/H] < -1.17$ dex, at 95% confidence)
stellar system with an absolute magnitude of $M_V = -1.5^{+0.4}_{-0.6}$ mag and
an azimuthally-averaged half-light radius of $r_{1/2} =10^{+4}_{-3}$ pc. These
properties are consistent with the population of ultra-faint star clusters
uncovered by recent surveys. Interestingly, DELVE 6 is located at an angular
separation of $\sim 10\deg$ from the center of the Small Magellanic Cloud
(SMC), corresponding to a three-dimensional physical separation of $\sim 20$
kpc given the system's observed distance ($D_{\odot} = 80$ kpc). This also
places the system $\sim 35$ kpc from the center of the Large Magellanic Cloud
(LMC), lying within recent constraints on the size of the LMC's dark matter
halo. We tentatively measure the proper motion of DELVE 6 using data from
$\textit{Gaia}$, which we find supports a potential association between the
system and the LMC/SMC. Although future kinematic measurements will be
necessary to determine its origins, we highlight that DELVE 6 may represent
only the second or third ancient ($\tau > 9$ Gyr) star cluster associated with
the SMC, or one of fewer than two dozen ancient clusters associated with the
LMC. Nonetheless, we cannot currently rule out the possibility that the system
is a distant Milky Way halo star cluster.
