  In this paper, we report our first-step results of high resolution
He\,\textsc{i} 10830 \AA\ narrow-band imaging (bandpass: 0.5 {\AA}) of an M1.8
class two-ribbon flare on July 5, 2012. The flare was observed with the 1.6
meter aperture New Solar Telescope at Big Bear Solar Observatory. For this
unique data set, sunspot dynamics during flaring were analyzed for the first
time. By directly imaging the upper chromosphere, running penumbral waves are
clearly seen as an outward extension of umbral flashes, both take the form of
absorption in the 10830 \AA\ narrow-band images. From a space-time image made
of a slit cutting across a flare ribbon and the sunspot, we find that the dark
lanes for umbral flashes and penumbral waves are obviously broadened after the
flare. The most prominent feature is the sudden appearance of an oscillating
absorption strip inside the ribbon when it sweeps into the sunspot's penumbral
and umbral regions. During each oscillation, outwardly propagating umbral
flashes and subsequent penumbral waves rush out into the inwardly sweeping
ribbon, followed by a returning of the absorption strip with similar speed. We
tentatively explain the phenomena as the result of a sudden increase in the
density of ortho-Helium atoms in the area of the sunspot being excited by the
flare's EUV illumination. This explanation is based on the observation that
10830 \AA\ absorption around the sunspot area gets enhanced during the flare.
Nevertheless, questions are still open and we need further well-devised
observations to investigate the behavior of sunspot dynamics during flares.
