. . .
The swarm is finite. It will be years before the first scissors that missed the Earth can turn about and head back — they are slung around the well of Earth’s gravity, pushed off by its sun, captives to their own momentum and to dread ballistics’ laws; it will not be until they reach Alpha Centauri (for some) and Wolf 359 (for others) that they will be able to turn themselves around for another strafe.
As for those that hit the Earth, they are denatured and defeated: on planet Earth, a pair of scissors can kill you once, when it falls from space, maybe twice, if somebody picks them up and runs with them, maybe even three times if they split a car’s tire and send it veering from the road — but ultimately, once they strike the ground, they cannot move.
So the world weathers the killing rain.
Time passes.
The scissors (and one screaming, burning jaguar) cease to fall.