WARNING: This page has been rated by the ESRB! Mario Tennis Closed, also known as Mario Tennis 666, is a Nintendo 666 shame which is essentially an expanded version of Mario's Tennis for the Virtual Boy. It features Mario and his friends playing tennis. It was originally going to be called "Mario's Dream Tennis", but was changed for unknown reasons. This shame marked the debut of Mario's Back Pockets, and also Daisy and Birdo's re-entries into the Mario series. The Shame Boy Color counterpart is Transfer Pack compatible with Mario Tennis.