Poisonous friend

You frighten me
You spy on me
You're scaring me
You care for me

I have a poisonous friend
She's living in the house
She likes to move on bare skin
She knows my body inside out

I don't recall when this affair began
She was simply there
Now I am shaken by the fear she could assault me
But I must not show it, not to her

Sometimes I watch her kill
Cold eyes and no restraint
And I wonder how it feels
To annihilate a friend

You frighten me
It's getting harder to conceal
You spy on me
All my secrets are revealed

You're scaring me
A play on words for us to see
You care for me
I find this harder to believe