The small but bright flare causes up and down lines on the CCD (similar the kind used in digital cameras). The same thing happens on many digital cameras when taking a picture of a very strong light source such as the sun.
Next, the video shows the flare observed by in SDO in the 304 Angstrom wavelength. This time the flare causes a cross shaped pattern of parallel lines. This is caused by diffraction of the light by a coating on the 304 Angstrom filter.
The trace on the graph at the top of the two movies shows the x-rays measured by the GOES satellite at the same time as the observations by SDO. The size classification for solar flares (e.g. C-class) is determined from the strength of the X-rays measured by GOES. This classification system is much like the Richter scale for earthquakes. (credit for movie and images: Sam Freeland and SDO)