Madame La Costa.
Quintessential operatic "fat lady" known as "CONTROL's singing agent".
Madame La Costa is assigned to assist Maxwell Smart and 99 in rescuing Professor Phineas Pheasant from KAOS headquarters in New Jersey by singing a note pitched highly enough to shatter the nuclearized-glass cell in which he is being held.
When this fails, she simply walks into the cell, her sturdy frame causing the cell to fall apart on contact.
Portrayed by Virginia Jaeger [Episode #113: "Pheasant Under Glass"].