But if you do see it gobble planets and stars, they you know Remina is on the way! ;-)
Where is the 250 million years come from?
There are a number of likely mass-extinction / life-terminating events which will occur within the next billion or so years, either deterministically or probablisticaly (e.g., increased solar insolation and plate tectonics are deterministic, massive gamma-ray burst or killer asteroid are probabalistic), of which supercontinent-formation is only one.
Wikipedia's "Timeline of the Far Future" lists several:
<https://en.wikipedia.org/wiki/Timeline_of_the_far_future>
We likely exist in the late afternoon if not evening of Earth's habitable period.
Perhaps a reference to Pangea Proxima?
https://en.wikipedia.org/wiki/Pangaea_Proxima
Life might very well exist on earth even through those conditions, but not to the extent we have today.
Direct interaction isn't needed for havoc. A supermassive object sweeping by the Solar System could destabilize Jovian orbits. In the Nice model, Neptune flung Kuiper belt asteroids sunward, gifting the inner planets with a late heavy bombardment.
Rogue gas giants, brown dwarfs accelerated to relativistic speeds, giant asteroids approaching from the Sun's direction, Carrington Events, an ill-directed gamma ray, etc. So many ways life on Earth can see its 250 million remaining years cut short, and those are only a few of the cosmic threats we can imagine.
A black hole with a Schwarzschild radius of 20 km would weigh about 6.8 Solar masses. It wouldn't even need to get super close to affect the Solar System.