What is the term for a dream in which the dreamer realizes they are dreaming while asleep?

A sleeping person cannot know that they are dreaming, for sleep resembles death in the cessation of consciousness and movement. Allah Almighty described it as such, for example, in His saying: "Allah takes the souls at the time of their death, and those that do not die [He takes] during their sleep." So, a sleeping person is not in the same mental state as when they are awake, and therefore, they are excused from fulfilling obligations.