gistfile1.js

function HugeAnimal(name) { 
    Animal.apply(this, arguments)
}

HugeAnimal.prototype = new Animal 
HugeAnimal.prototype.constructor = HugeAnimal 
HugeAnimal.prototype.toString = function() {
    return 'im ' + this.name + ' a ******* huge animal' 
}

print(new HugeAnimal('Simon'))
// => 'Im Simon, a ******* huge animal'