  Cold, substellar objects such as brown dwarfs have long been recognized as
contaminants in color-selected samples of active galactic nuclei (AGNs). In
particular, their near- to mid-infrared colors (1-5 $\mu$m) can closely
resemble the V-shaped ($f_{\lambda}$) spectra of highly-reddened accreting
supermassive black holes ("little red dots"), especially at $6 < z < 7$.
Recently, a NIRCam-selected sample of little red dots over 45 arcmin$^2$ has
been followed up with deep NIRSpec multi-object prism spectroscopy through the
UNCOVER program. By investigating the acquired spectra, we identify three of
the 14 followed-up objects as T/Y dwarfs with temperatures between 650 and 1300
K and distances between 0.8 and 4.8 kpc. At $4.8^{+0.6}_{-0.1}$ kpc,
Abell2744-BD1 is the most distant brown dwarf discovered to date. We identify
the remaining 11 objects as extragalactic sources at $z_{\rm spec} \gtrsim 5$.
Given that three of these sources are strongly-lensed images of the same AGN
(Abell2744-QSO1), we derive a brown dwarf contamination fraction of $25\%$ in
this NIRCam-selection of little red dots. We find that in the near-infrared
filters, brown dwarfs appear much bluer than the highly-reddened AGN, providing
an avenue for distinguishing the two and compiling cleaner samples of
photometrically selected highly-reddened AGN.
