The Special Guest Referee is any match in which the usual referee is replaced with a "guest" filling in as the official. Celebrities (such as Muhammad Ali in the main event of WrestleMania I), managers and other wrestlers can "guest" as the special referee. In some cases, a special referee is put into a match which is already a different match type or stipulation. The special referee will often be biased towards or against one of the competitors or will be assigned as the Special Referee to ensure the match is called down the line. Special Outside Referee