This is a Yokai from Japanese folklore, the Nurikabe manifests itself as a wall. It tries to impede or misdirect travellers in the night time. This would be completely futile though, as it extends itself forever, but lore has it that knocking on the lower part of the wall will make it go away. The legend is believed to have originated as an explanation for travellers losing their bearings on long journeys
Pop culture Nurikabes in Japan: So wonderful!
Info and Pic from Tumblr