obviously this was a spirit knock: when a thing or being spirit knocks on your wall, wanting to be let in to your world. its a LOUD powerful knock. beware if you hear multiple knocks. What happens next? What do you do?

You either ignore the knock, or you YOURSELF knock 3 times back on your wall, to allow the spirit demon inside the earthly plain. Spirits can only be let in though your knock sound vibrations, thats why they need you to knock back, 3 times, to let them into this reality dimension zone. Spirits and anything can be heard by those whom listen, people say they hear voices all the time, schizophrenics, but anybody can hear voices if they simply decide to listen to that radio signal of the voice. Birds chirping, flowers singing, dead people wailing, all can he heard by ANYONE for those whom listen and attend their ears outward towards that dimension calling out.