A static_cast can convert a base pointer down to a derived pointer when you already know the real object type, letting you call methods that only exist on the derived class.

Base class Animal has a virtual string name() const returning "animal".
Derived class Dog overrides name() to return "dog" AND adds a Dog-only method string fetch() const returning "fetching".

The runner holds an Animal* that actually points to a Dog, downcasts it with static_cast<Dog*>, and calls fetch(). The program prints:
fetching

Do NOT write a main function.