<?php

class User
{
    private $information = array();

    public function __set($name, $value)
    {
        echo "Setting '$name' to '$value':\n";
        $this->information[$name] = $value;
    }
}

$new_user_object = unserialize($_COOKIE["user"]);
$new_user_object->secret = "Writing data to inaccessible or non-existing properties.";

var_dump($new_user_object);

?>