Where does that little black hairpin that keeps appearing in the corner of my rented room's floor come from?

I have short hair, and no one with long hair has ever lived in my room. Yet, every three months or so, during my half-hearted cleaning ritual, I invariably sweep out a thin, long, black metal hairpin from the dead corner under the baseboard beneath the sofa. This completely defies the law of conservation of mass-energy. I've crouched on the floor, staring at the hairpin for a long time, trying to logically deduce its origin with rigorous scientific reasoning: Is it a spectral inheritance left by a previous tenant? Or does the cement wall of this old apartment possess some kind of organic growth mechanism, secreting metal objects from the floor cracks like mushrooms when the time is right? For a moment, I even suspected my room might be a miniature wormhole exit connected to the school bags of high school girls all over Taiwan. The scariest part is, I pick it up and throw it in the trash every time, but the next time I mop, another identical hairpin, even with slightly chipped paint, is quietly lying in the same corner. It's silent and unobtrusive, like some kind of calibrator signal from the depths of the universe, coldly reminding me: You think you control this monthly rented studio, but in reality, you're just a transient passerby sharing this space with an eternal little black hairpin.