At the current technology level of the human species, it takes months for them to reach the nearest planet to theirs.
It took nearly 50 for something they made to even break into interstellar space, and even then, it’s dubious to say it’s proper interstellar space.
For them to reach the next nearest star, it would take thousands of years.
There are species like this across the universe, trying to find their way or to make their mark on a cosmic abyss that doesn't care for them.
By and large they're left to their own devices; they're too small and insignificant to be of any real concern to the real life that exists out there.
The space between planets and stars is nothing compared to the space between galaxies, yet in some ways, dealing with the latter is easier.
Many of the older species have found their own way to travel across these distances, and since there's nothing between galaxies – nothing of any real importance, anyway – many of them opt for the travel in a straight line and hope for the best approach. An approach which has seen the end of many stars and planets when tried inside of a galaxy.
These older species don't tend to travel from galaxy to galaxy, however. There have been individuals, or groups of individuals who have, but to them, one galaxy is the same as the next.
There is one species, however, that does travel between galaxies regularly. A parasitical species that lives for, in some cases, hundreds of thousands of years.
There aren't many of these creatures, maybe a little more than a dozen, across the entire universe and for those who know of them, the ever present fear is that they are allowed to establish a foothold anywhere.
They are born from an egg which lives on the fringes of, or just outside, a host galaxy. The egg is the size of a large planet and when the creature hatches after its few thousand year incubation, it explodes with such ferocity that some civilisations are wiped out by the fragments.
Its juvenile stage is a journey to the supermassive black hole at the centre of the galaxy. Once there, it starts to suck in all the detritus that has gathered around the outside of the black hole, effectively starving it and causing it to shrink, all the while growing itself.
When it is big enough and the black hole is small enough, the creature eats it. It’s at this point it changes into its adult form. It lengthens into a worm, up to half the diameter of the galaxy itself. The genetic memory of its ancestors is released and it becomes intelligent and metabolises the black hole into the energy it requires to lay its own eggs.
It takes, on average, 20,000 years from hatching until it reaches full maturity. During its journey from the outer rim of the host galaxy to the centre, it destroys countless planets and stars, absorbing some of their energy as it passes, but leaving most of it to disperse into the galaxy, which itself causes untold devastation.
In its adult form, the creature consumes a huge swathe of whats left of the galaxy and starts the next leg of its life cycle, travelling to the next nearest galaxy to lay its eggs. A journey which takes most of the rest of its life.
At least, that's what usually happens. There are several other long lived species who have made it their job to monitor these creatures. They know that if these creatures are allowed to expand out through the universe, they will irreparably harm more and more galaxies. These people watch. Watch and ensure that only one or two eggs from any given worm are allowed to become viable. Currently, the estimated the upper limit allowable is 24 of these beings.
Their current estimate as to how many there are is 15. An armada of ships follows each creature until it dies in the process of egg laying, at which point it sets up a planet just inside the galaxy from where the egg is and builds a civilisation. Ready and waiting to follow the hatchling whenever it should appear.
The creature has just swallowed the black hole. The armada is fully formed and is watching from above as the creature goes through the transformation process.
The crew has an extensive list of markers to determine where in the process it is and what it’s likely to do next. However, even species which have such a history can be surprised.
The flagship Hedion, captained by one of the more admired leaders amongst his people, is sitting some five light years out from the head of the creature, with the rest of his fleet set in positions around the rest of its body.
By all reckoning, it had been several thousand years since the black hole had been absorbed and the transformation should be done, or very close to being done, yet the creature had yet to make any signs that it was moving on. In fact, some in the armada had reported it was bringing its body in close to its head, a sign they claimed meant it was planning on staying where it was.
The captain, who was not a man to react quickly made sure that all his subordinates recorded everything, and every other ship in the armada did likewise.
In the absence of anything else to do, he also radioed the other armadas, out there amongst the stars, about what they had witnessed, or potentially witnessed, just in case something similar happened with the other creatures. He didn't expect to be alive when any response was heard, so he put it to the back of his mind.
It was some years later, the armada had shifted and the organisational charts had been altered, but the captain of the Hedion was still in charge and he was getting concerned.
The creature, now fully adult, should have been on its way to another galaxy to lay its eggs, however it had started to coil itself up underneath where the black hole used to be.
On top of which, it had started sending out some sort of inaudible signal. The best case scenario was that nothing out there could hear it except the armada’s receivers. The worst case, as some people said, was that it was calling to others of its kind.