Evolution of the SJI and spectral data through time. The first and final SJI frames (top left and top middle panels) show that the transition region brightening remained relatively stable with only a small increase in the size of the northern brightening. The blue vertical lines indicate the slits over which the spectra were averaged in the remaining panels. Spectra from the second and second-to-last raster steps (black and blue lines, respectively) display an increase in intensity in all pass-bands during the supersonic downflow, however, only the O IV and Si IV lines possess the second peak in intensity in the red wing indicative of supersonic downflows. The vertical dashed pink lines indicate the rest wavelengths of the lines of interest.