A mouse in my house

I have a mouse, up in my house,
I hear him in the wall.

He came inside, just last night,
Outside it is too cool.

His scratchy feet, they run about,
the ceiling is his yard.

He looks for friends, companionship,
he always tries so hard.

His lonely vigil does go on,
a friend is all he needs,
I opened the door, just one more,
a friend he gained indeed.

So now there's two, double the poo,
they scratch about all night.

But now I hear, with my trained ear,
their squeals of delight.