  Using the novel $JWST$/NIRCam observations in the Abell 2744 field, we
present a first spatially resolved overview of an $HST$-dark galaxy,
spectroscopically confirmed at $z=2.58$ with magnification $\mu\approx1.9$.
While being largely invisible at $\sim$1 $\mu$m with NIRCam, except for sparse
clumpy sub-structures, the object is well-detected and resolved in the
long-wavelength bands with a spiral shape clearly visible in F277W. By
combining ancillary ALMA and $Herschel$ data, we infer that this object is an
edge-on dusty spiral with an intrinsic stellar mass log$(M_*/M_\odot)\sim11.3$
and a dust-obscured SFR$\sim 300~M_\odot$~yr$^{-1}$. A massive quiescent galaxy
(log$(M_*/M_\odot)\sim10.8$) with tidal features lies 2\farcs{0} away
($r$$\sim$9 kpc), at a consistent redshift as inferred by $JWST$ photometry,
indicating a potential major merger. The dusty spiral lies on the main-sequence
of star formation, and shows high dust attenuation in the optical ($3<A_{\rm
V}<4.5$). In the far-infrared, its integrated dust SED is optically thick up to
$\lambda_0 \sim 500$ $\mu$m, further supporting the extremely dusty nature.
Spatially resolved analysis of the $HST$-dark galaxy reveals a largely uniform
$A_{\rm V}\sim 4$ area spanning $\sim$57 kpc$^2$, which spatially matches to
the ALMA 1 mm continuum emission. Accounting for the surface brightness dimming
and the depths of current $JWST$ surveys, unlensed analogs of the $HST$-dark
galaxy at $z>4$ would be only detectable in F356W and F444W in UNCOVER-like
survey, and become totally $JWST$-dark at $z\sim6$. This suggests that
detecting highly attenuated galaxies in the Epoch of Reionization might be a
challenging task for $JWST$.
