Here is a weird thing that is totally real: when someone screams out their window in Sweden, Sweden screams right back.

Responding to a scream with a scream isn't exactly what one would consider proper protocol — because, you know, trouble may be ahead — but when you live in the IKEA nation it's just how things are done. They're not inconsiderate prickigs (those are microwave covers), they're just following tradition, and it is called The Flogsta Scream.

Reddit user BuffPiggy posted a video of what happens when you scream out your window at night:

Yeah, screaming into the dark of night isn't a source of unsettlement, it's a point of pride. The Huffington Post has previously covered the phenomena and confirms this is a real thing—The Flogsta Scream is one of those totally legitimate Swedish things that makes no sense to outsiders such as us.

Beginning in the 1970s, students in the Flogsta neighborhood of Uppsala, Sweden started sticking their heads out the window at 10PM every night to scream into the darkness. It's a veritable symphony of woe. Apparently it began in the 1970s and has been going on — no joke — every single night since it started. Some reports say it began as a stress reliever during exam times, others say it was in honor of a student who committed suicide.

Whatever the case, it's a pretty cool tradition and way to let off steam, even if the rest of us will still feel a little scared when it happens.