Can you destroy a script with the same script? I mean, with an ontriggerentrer an action passes, then can I delete ONLY the script without destroying the entire object? and how?
Yes, a MonoBehaviour class represents a component on the GameObject, not the GameObject itself. If you call "Destroy(this)" the component is destroyed. "this" is a C# keyword that serves as a reference to the current class instance. If you call "Destroy(gameObject)" the whole GameObject is destroyed. "gameObject" is a MonoBehaviour-provided reference to the GameObject that "this" component is attached to.
Instance. This reference to currently executing class instance. A class may have multuple instances. To reference the class itself, call this.GetType();
On the forum we often throw around the term "script" casually, but mean a few different things depending on context. As already touched on, you generally have a MonoBehaviour class and then instances of that MonoBehaviour class attached to GameObjects. Yes an instance of a MonoBehaviour class can destroy another instance of the same MonoBehaviour class (or even itself). Just get a reference to the instance you want to destroy. You can also disable the instance of that class, which is often preferable (since you give yourself the option to re-enable it later).