The Red Crayon

This is a story I heard from my friend, who works in an estate agent.
There was a flat he was in charge of, and one of its rooms always gave him a strange feeling every time he stepped in it. Something was not quite right about it, but he could not put a finger on what it was. Then one day he thought he found out the reason; he spotted that the passage next to the room was about one metre shorter than it should be. He went to the end of the corridor and knocked on the wall. And from the sound being made he deduced that there was a small space between the original wall and the one he was knocking on. He thought that was odd and decided to investigate further. Having first got permission from his boss, he pulled down the wall.

“I would have felt better if I’d found a skeleton or something in there,” my friend told me later about his experience.
In reality what he found inside was a certain word, repeated again and again, written all over the walls.
“Mummy mummy mummy mummy mummy mummy mummy mummy mummy……,”so the word ran endlessly, in red crayon.

In the end they decided to put the wall back into place, leaving the place as it was, without erasing the words. After that he promptly handed over the charge of the property to other colleague.