What's the title of this movie?

I remember seeing a movie when I was younger, where you would look in the mirror and your reflection would kill you. And there was a specific part I remember where a mother asks her son who he's talking to, and he points to the mirror and says "my friend" and it is actually his reflection who tries to kill him, and when his mom looks in the mirror, her reflection kills her. Anyone know the name of this movie?