Nicolas Stuart Gray

Does anyone know of a particular book of short stories by Nicholas Stuart Gray? One of the stories was followed a group of children going to see the alien. The "alien" turned out to be a human. I remember the shock of reading the description of a human hand. I lent this book and it was never returned

I suspect this would be "The Star Beast" in Mainly in Moonlight.

I know the Star Beast - It isn't that one. I think it was called Blot on the landscape