peryton

A fictional creature having the head and forelegs of a stag and the wings and hindquarters of a bird.

Then, quite unexpectedly, when I had been staring at them for a long time, the shape of a peryton seemed to spring out as distinctly as if the bird's whole body had been powdered with the dust ground from diamonds.

The peryton also makes an appearance, in a nod to its inventor, Borges — who compiled his own bestiary, “The Book of Imaginary Beings,” itself supposedly based on a long-lost medieval text.

A radio signal which appears to come from outside the galaxy but is actually produced by terrestrial sources.

Despite a trend mimicking that expected from dispersion, such deviations decisively distinguish the pulses’ frequency-dependence from a delay induced by interstellar propagation. Hereafter we distinguish these detections with the name “Perytons,” representing the non-dispersive, highly swept, terrestrial signals exhibited by the pulses. (The name is chosen from mythology to be unassociated with an exact physical phenomenon, due to the ambiguous origin of the detections; Perytons are winged elk that cast the shadow of a man.)

Three of these FRBs are factors of >3 narrower than any documented peryton.