At its most basic level, to cease to exist means to come to an end or to no longer be present in a physical state.
: It is frequently used in scientific or historical contexts to describe the total disappearance of a species or an ancient civilization, like the city of Petra. 2. Philosophical and Existential Themes Cease To Exist
The concept often triggers "existential dread" because humans find it difficult to imagine true nothingness. At its most basic level, to cease to