It's happened.
Right when you read that line, you immediately forgot something.
Something? Yes. Maybe it was your birthday. Maybe it was your mother's birthday. Maybe it was your mother's existence. Whatever it was, you've forgotten it. You're never going to get it back.
I have placed you into a mindset that what you forgot never existed. I have changed your memory, so that you remember a life without it. I have changed your world, so you are living a life without it. Had I never told you, you'd never have known you had forgotten it.
But that's okay, it's just a small change. Isn't it?