Long story short.
Our one is not the first nor the most evolved human civilization. About 80.000 years ago, Hoi people conquered the galaxy. FTL spaceship were quite expensive so the actual colonization had to rely on a different transport. Hoi found a way to open permanent tunnels across dimensions. Core of this technology was a multi-dimensional creature they named Tada Harr (a now extinct little mole-like mammal). Tada Harr should have been just a device but the amount of data needed to its system made it self-conscious. Having such a powerful creature out of control could have been a tremendous danger but Tada Harr just loved human beings and tried its best to not prevaricate them.
By the way, she loved to appear in the shape of a pretty girl on the ship which were crossing the tunnels. She also loved to entartain the crews and the passengers by singing songs, too bad she had a terrible voice. Of course, nobody ever dared to complain about. How she had to shut down herself to save human race is a different story.
Click buttons to start or stop the tune. Drawing and music by me.