Re: Uh, am I the only one
And to only last 2ms and never be repeated over decades, it's the universe's most inefficient radar.
These things are literally blips, probably caused by the little "spikes" that you see poking out of any non-spherical object (because it's spinning ridiculously fast), literally a beam shooting out, at random, powerful enough to reach across the cosmos (but not back in any vaguely sensible time!).
You know when you have those "two spheres meeting" graphics that look like an hourglass (because of gravity) and around the middle you have a beam at right angles just shooting out? It's that kind of thing. Something spinning stupendously vast, with a tiny narrow beam coming out of it, which only ever skirts us once by sheer chance and could spin for a billion years without actually pointing out exact way again (the angular arc required to hit Earth from that distance is incredibly tiny).
This is why they are rare, fleeting, impossible to predict, rarely repeat, and yet intense enough to notice when you go looking for them in the data.