If it is possible for something to exist, the odds of it actually existing increase directly proportionate to the size of the universe. Since as far as we know, the universe is infinitely large, almost everything that can exist probably does exist.
Including large bodies of mass moving near light speed. Now, a meteor striking the earth is not at all lame. In fact, its pretty much the driving plot of several movies and episodes of popular series. What isn’t a driving plot is going from danger to game over faster than you can say “Sir, I think I see something in the telescope”
If a large enough meteor were to have managed to reach near light speed; it would be able to approach the earth almost as quickly as it’s image would appear in any telescope. It would basically be the space equivalent of a train coming out of nowhere to splat a character in the last 5 seconds of the show.