  We analyze the light curve of the M5.5 dwarf Proxima Centauri obtained by the
TESS in Sectors 11 and 12. In the $\approx 50$ day-long light curve we
identified and analyzed 72 flare events. The flare rate was 1.49 events per
day, in total, 7.2% of the data was classified as flaring. The estimated flare
energies were in the order of $10^{30}-10^{32}$ ergs in the TESS passband
($\approx4.8\times$ higher in bolometric energies, but in the same order of
magnitude). Most of the eruptions appeared in groups. Two events showed
quasi-periodic oscillations during their decay phase with a time scale of a few
hours, that could be caused by quasiperiodic motions of the emitting plasma or
oscillatory reconnection. From the cumulative flare frequency distribution we
estimate that superflares with energy output of $10^{33}$ ergs are expected to
occur three times per year, while a magnitude larger events (with $10^{34}$
ergs) can occur every second year. This reduces the chances of habitability of
Proxima Cen b, although earlier numerical models did not rule out the existence
of liquid water on the planetary surface. We did not find any obvious signs of
planetary transit in the light curve.
