all of a sudden.......
All of a sudden the group was enshrouded in the fog
Her words were the catalyst for my sudden, yet, percise actions.
There was a sudden disturbance in the antechamber, with a confused sound of cries and shouting.
Her appearance was horrible.The sudden appearance of the monster startled me.
The motorcycle's sudden acceleration snapped his neck like a twig.
I was startled by a sudden noise.
There was a sudden disturbance in the antechamber, with a confused sound of cries and shouting.
The bus stopped with a sudden jolt.
It is called an exclamatory sentence.
You are unnerving me. That is one way you can use unnerving in a sentence.
The dean's sudden appearance in the room immediately rendered the entire class immobile.