The enemy tries with interface objects

in my scene I have an enemy that must be close to objects created at runtime. I thought of making an interface called “ISwanable”. The problem is that this interface does not do anything. I use it only as a component. And 'the right thing? how can I do instead?

You mean that it’s an empty marker interface? Something like:

public interface ISwanable {

}

That’s fine - I find it much cleaner than using tags to mark the object, or some other solution.