  We report the discovery of the most eccentric transiting brown dwarf in the
brown dwarf desert, TOI02490b. The brown dwarf desert is the lack of brown
dwarfs around main sequence stars within $\sim3$~AU and is thought to be caused
by differences in formation mechanisms between a star and planet. To date, only
$\sim40$ transiting brown dwarfs have been confirmed. \systemt is a
$73.6\pm2.4$ \mjupnospace, $1.00\pm0.02$ \rjup brown dwarf orbiting a
$1.004_{-0.022}^{+0.031}$ \msunnospace, $1.105_{-0.012}^{+0.012}$ \rsun
sun-like star on a 60.33~d orbit with an eccentricity of $0.77989\pm0.00049$.
The discovery was detected within \tess sectors 5 (30 minute cadence) and 32 (2
minute and 20 second cadence). It was then confirmed with 31 radial velocity
measurements with \feros by the WINE collaboration and photometric observations
with the Next Generation Transit Survey. Stellar modelling of the host star
estimates an age of $\sim8$~Gyr, which is supported by estimations from
kinematics likely placing the object within the thin disc. However, this is not
consistent with model brown dwarf isochrones for the system age suggesting an
inflated radius. Only one other transiting brown dwarf with an eccentricity
higher than 0.6 is currently known in the brown dwarf desert. Demographic
studies of brown dwarfs have suggested such high eccentricity is indicative of
stellar formation mechanisms.
