A Wizard is a user, in addition to Acme Head rights, who can grant/revoke Rollback, Head, and Wizard rights. While Wizards cannot directly remove other user's Wizard status, a Wizard may remove their own usergroup. Remember wizards are also Acme Heads because if a Wizard was only a wizard, they couldn't edit protected pages.
Wizards can also be referred to as Bureaucrats.
Who are the wiki's Wizards?
These were all demoted due to inactivity, or had their accounts disabled.