What happens to an object if it becomes completely missing and cannot be found?

The selection of "disappeared" is fitting because it indicates a state in which an object is no longer visible or cannot be located. The term conveys a complete absence and aligns with the idea of something being missing or unable to be found. It suggests that the object was once present but has now become untraceable.

The other terms have distinct connotations. "Vanished" could also imply that something has suddenly or mysteriously gone missing, but it often suggests a more dramatic or sudden disappearance. "Fled" typically refers to a person or animal escaping from a place or situation, which does not apply to inanimate objects. "Evaporated" generally describes a physical change from liquid to gas, and while it can metaphorically imply something has disappeared, it is usually not used to describe objects that are simply missing. Therefore, "disappeared" is the most straightforward and appropriate choice in this context.