<?php

class Human
{
    private $name;

    public function __construct($name)
    {
        $this->name = $name;
    }

    public function touch($human)
    {
        $human->name = "Ahtung";
        return "Touched $human->name";
    }

    public function getName()
    {
        return $this->name;
    }
}

$john = new Human("John");

$sully = new Human("Sully");

$john->touch($sully); // Touched Sully

echo $sully->getName();