  We present an extensive analysis of the optical and UV properties of
AT2023clx, the closest TDE to date, that occurred in the nucleus of the
interacting LINER galaxy, NGC3799 (z=0.01107). From several standard methods,
we estimate the mass of the central SMBH to be ~ 10^6 Msol. After correcting
for the host reddening (E(B-V) = 0.177 mag) we measured its peak absolute
g-band magnitude to be -18.25\pm0.05 mag, and its peak bolometric luminosity to
be L_pk=(3.24\pm0.36)x10^43erg/s, making AT2023clx an intermediate luminosity
TDE. The first distinctive feature of AT2023clx is that it rose to peak within
only 10.4\pm2.5 days, making it the fastest rising TDE to date. Our SMBH mass
estimate rules out the possibility of an intermediate mass BH as the reason of
the fast rise. Dense spectral follow-up revealed a blue continuum that cools
slowly and broad Balmer and HeII lines as well as weak HeI emission, features
that are typically seen in TDEs. A flat Balmer decrement (~ 1.58) suggests that
the lines are collisionally excited rather than being produced via
photoionisation, as in typical active galactic nuclei. A second distinctive
feature, seen for the first time in TDE spectra, is a sharp, narrow emission
peak at a rest wavelength of ~6353 A. This feature is clearly visible up to 10d
post-peak; we attribute it to clumpy material preceding the bulk outflow, and
manifested as a high-velocity component of Ha (-9584km/s). The third
distinctive feature is a break observed in the near-UV light curves that is
reflected as a dip in the temperature evolution around ~18-28 days post-peak.
Combining these findings, we propose a scenario for AT2023clx involving the
disruption of a very low-mass star (<=0.1Msol) with an outflow launched in our
line-of-sight with disruption properties that led to circularisation and prompt
and efficient accretion disc formation, observed through a low-density
photosphere.
