A bot that crawls MyBB forums as a logged in user.
Open up bot.php and change the site URL to your own. Define the mybbuser constant as well. If you don't know how to find your cookie, upload cookie.php and access it to find the cookie value. Opera has a built in cookie viewer, and FireFox and Chrome have extensions if you don't own the site or have access to FTP.
Tidy up code more. Perhaps add forbidden pages like newthread, etc.