  Extremely peculiar emission lines have been found in the spectra of some
active galactic nuclei and quasars. Their origin is totally unknown. We
investigate the hypothesis that they are generated from ultra-rapid
quasi-periodic oscillations that may occur in jets or black holes, as predicted
in a published theoretical paper. We conclude that, although not totally
certain, this hypothesis is just as valid as the other highly peculiar
hypotheses that have been previously made (e.g. blueshifts due to bulk motions
close to the speed of light). We consider ways to further validate our
hypothesis.
