Suspense.

Suspense is a feeling of uncertainty and anxeity about the outcome of certain actions, most often referring to an audience's perceptions in a dramatic work. Suspense is not exclusive to fiction, though. Suspense may operate in any situation where there is a lead-up to a big event or dramatic moment, with tension being a primary emotion felt as part of the situation.

You usually have suspence in in thriller movies and horror movies, and it creates a certain atmosphere, when everyone is quiet and all of a sudden something will jump out, or explode, anything that will make the audience jump. You also associate suspense with adrenaline.