I have an index.php file that has 3 includes

<?php
require_once('mod.php');
$mod = new Mod();

require_once('start.php');
require_once('tools.php');

....some code....
?>

I need to be able to reference the $mod object inside the start.php and tools.php. How do I pass that object to be referenced by those 2 other require files?

Basically the mod.php is a class that has an array list generated in its __construct(). I want to use that array list data inside the startup.php and tools.php file but not sure how to pass in the existing one without calling "new" inside both of those files separately which doesn't do what I need since it resets everything.

Thanks!