Chapter six from volume nine of the Horror World of Junji Ito Collection, Hallucinations.
Oshikiri has been suffering from hallucinations and believes that there is a living presence in his house. He is beginning to regret his decision to stay in Japan alone while his parents moved overseas for work. Recently, Oshikiri has begun to hear what sounds like insects crawling within the walls. He visits his cousin Takayuki, who suggests that his father clear it with Oshikiri's parents for Oshikiri to move in with the family. There is suddenly a violent earthquake, and Takayuki and Oshikiri shelter under the table. Oshikiri stays the night with Takayuki, but when he gets home the next day, part of the wall has collapsed during the earthquake. He is shocked to discover a mummified corpse inside the wall.
Oshikiri begins researching into his family history, trying to find out why the dead body was inside the wall. He comes across a photo of a man whose upper body is sticking out from the wall. The wall now has a picture hanging there and Oshikiri figures that the man was cut in half, and the picture was hung to hide where his mutilated remains had been. Oshikiri checks behind the picture, but there is no sign of the wall being sealed, even though he's sure it is the same spot.
Oshikiri does not want to call the police because, further to the events of the previous story, his counterpart from an alternate universe murdered three of Oshikiri's friends and buried them on the grounds of the house. However, the mummified body has been there too long for the alternate Oshikiri to have been responsible. Oshikiri's parents are coming back for a visit, so he needs to get rid of the corpse that he found in the wall. He can't repair the wall himself so he decides he'll dig out the corpse, bury it on the grounds, and just say that the wall collapsed during the earthquake. However, when he tries to remove the corpse from the wall, he hears a scream that sounds familiar.
That night, Oshikiri begins hearing noises from inside the walls again. He contemplates going to Takayuki's house but, when he goes downstairs, his parents are at the door having come back early. He tries to explain away the corpse inside the wall but they can't see anything and believe he is hallucinating. Oshikiri shows them the photo of the man sticking out from the wall. He notices that his mother's arm is bandaged, but she says it's a burn injury, and evades his questions. Oshikiri's father decides the photo is a trick, and decides to burn it. He takes out his lighter, but has to stop when his wife screams at the sight of the flames.
The phone rings and Oshikiri goes to answer it. It is his mother, who abruptly says that she and his father won't be coming back to Japan as they are too busy with work. Oshikiri realizes this is his real mother. The parents who just arrived come into the room, and cut the phone cord. They tell him they are from the alternate dimension, but they lost their home in the earthquake, so they came to live in this one instead. They are waiting for their son (the evil alternate Oshikiri) to join them.
At this point, the alternate Oshikiri screams from outside. Everyone races outside to see that his upper body is sticking out from the garden wall. He has failed to cross the dimensions properly, and now he's about to be absorbed by the wall. His parents try to pull him out, but get sucked in by the wall as well. Oshikiri realizes that the photo, and the corpse in the wall, came from the alternate dimension. The noises that he hears inside the walls are people from the alternate dimension. He wonders how many of them have crossed through into this world. When he looks up, he sees that all the outside walls of the house are covered in mummified corpses.