The name of the poem is “Antigonish” by Hughes Means and it goes like this:
Yesterday, upon the stair,
I met a man who wasn't there.
He wasn't there again today,
I wish, I wish he'd go away...
When I came home last night at three,
The man was waiting there for me
But when I looked around the hall,
I couldn't see him there at all!
Go away, go away, don't you come back any more!
Go away, go away, and please don't slam the door...
Last night I saw upon the stair,
A little man who wasn't there,
He wasn't there again today
Oh, how I wish he'd go away...