Yer not just a-kiddin’.
A 100-yard diameter rock could be parked at, say, L5, and held in reserve. While it would not be a quick launch, giving it a push using a really large plasma drive (not yet demoed) at just the right time and in the correct direction would deliver it basically without warning to a target area.
Wouldn’t have to be basketball-hoop accurate.
Boom! Major city erased.
And it would look like a natural event.
I think Barringer was a 100 meter rock- it probably wiped everything in a 200 mile circle!