  SDSS J163401.94$+$480940.2 is a non-jetted radio-loud narrow-line Seyfert 1
(NLSy1) galaxy. Optical monitoring of this object was carried out in two
intra-night sessions each $\geq$ 3 hrs with 3.6m DOT. Intra-night optical
variability (INOV) characterization is presented for the first time for this
source. We have detected an unexpected remarkable flare in one of two
monitoring sessions of SDSS J163401.94$+$480940.2, whose rapid brightening
phase implied a minute like doubling time of $\sim$ 22 minutes, thereby
approaching to the extremely fast minute like variability, observed from FSRQ
PKS 1222$+$21 at 400 GeV. The detection of a minute-like variability suggests
the existence of relativistic jets with a small viewing angle. We briefly
discuss the possible mechanisms for the non-detection of relativistic jets in
its Very Long Baseline Array (VLBA) observations.
