Read these passages:
MACBETH. Stars, hide your fires
Let not light see my black and deep desires.
-William Shakespeare, Macbeth, Act I, scene iv
LADY MACBETH. Come, thick night,
And pall thee in the dunnest smoke of hell,
That my keen knife see not the wound it makes.
-William Shakespeare, Macbeth, Act I, scene v
These lines help to create a scary tone by:
It uses personification to tell the stars to hide their fires. It also uses this to describe light as being able to see. There are also many descriptive words that make the tone more dark and scary.
