Not alone

You might think me mad,
But we are not alone,
At night when you're feeling sad,
And you hear a moan,
Do not worry as they will do no harm,
It is not the dead we must fear,
They don't want to cause alarm,
Just want to see you cheer,
It's hard for them to help you,
When you can not see them,
They want to give you a clue,
On how to be their chum,
Tis the living we must not trust,
One chance and a knife is in your back,
With one big thrust,
Everything turns to black.