Summon the Hellhounds: What Happens if you Scream in Sweden at Night

In Uppsala, Sweden there is a neighborhood called Flogsta where they open a window a 10pm and scream bloody murder. They call it "the Flogsta scream" that supposedly has roots in stress release during exam times or is in remembrance of a suicide from the 70s. Now they just do it for fun as a nightly ritual.

I think they are pretending to be demonic hounds from the pits of hell.