  $JWST$'s first glimpse of the $z>10$ Universe has yielded a surprising
abundance of luminous galaxy candidates. Here we present the most extreme of
these systems: CEERS-1749. Based on $0.6-5\mu$m photometry, this strikingly
luminous ($\approx$26 mag) galaxy appears to lie at $z\approx17$. This would
make it an $M_{\rm{UV}}\approx-22$,
$M_{\rm{\star}}\approx5\times10^{9}M_{\rm{\odot}}$ system that formed a mere
$\sim220$ Myrs after the Big Bang. The implied number density of this galaxy
and its analogues challenges virtually every early galaxy evolution model that
assumes $\Lambda$CDM cosmology. However, there is strong environmental evidence
supporting a secondary redshift solution of $z\approx5$: all three of the
galaxy's nearest neighbors at $<2.5$" have photometric redshifts of
$z\approx5$. Further, we show that CEERS-1749 may lie in a $z\approx5$
protocluster that is $\gtrsim5\times$ overdense compared to the field. Intense
line emission at $z\approx5$ from a quiescent galaxy harboring ionized gas, or
from a dusty starburst, may provide satisfactory explanations for CEERS-1749's
photometry. The emission lines at $z\approx5$ conspire to boost the $>2\mu$m
photometry, producing an apparent blue slope as well as a strong break in the
SED. Such a perfectly disguised contaminant is possible only in a narrow
redshift window ($\Delta z\lesssim0.1$), implying that the permitted volume for
such interlopers may not be a major concern for $z>10$ searches, particularly
when medium-bands are deployed. If CEERS-1749 is confirmed to lie at
$z\approx5$, it will be the highest-redshift quiescent galaxy, or one of the
lowest mass dusty galaxies of the early Universe detected to-date. Both
redshift solutions of this intriguing galaxy hold the potential to challenge
existing models of early galaxy evolution, making spectroscopic follow-up of
this source critical.
