Custom class cannot be cast

I created 2 classes in this code example: Monster and Zombie. Monster is a superclass and Zombie is a child class of Monster.

This is my code:

public class Main {
    public static void main(String[] args) {
        Monster monster = new Monster();
        monster = (Zombie) monster;

    }
}

This is the Monster class:

public class Monster {

}

And here is the other class called Zombie that extends Monster:

public class Zombie extends Monster {

}

When I run the main method, I get the following error:

class Monster cannot be cast to class Zombie (Monster and Zombie are in unnamed module of loader 'app')

I only get the error in runtime. For context: I was following this tutorial.

Answer

it means you cannot turn the monster into a Zombie. Since Zombie is an extension of Monster, you would you something like this:

Monster monster = new Zombie();

does it work now?