the fright of (one's) life
An extreme and sudden sensation of shock, surprise, or fear. Usually used after the verbs "get" or "give." Seeing the car swerve right in front of her gave Mary the fright of her life. I got the fright of my life when I noticed someone standing right behind me.
the ˌfright of your ˈlife
an experience that makes you feel great fear: I got the fright of my life when I saw the gun pointing at me.He gave me the fright of my life when I saw him hanging out of the window.