Which river in the English county of Warwickshire has a ferry named after the main antagonist from the William Shakespeare comedy Twelfth Night?
Stratford-upon-Avon chain ferry: The Stratford-upon-Avon chain ferry is a manually operated pedestrian chain ferry across the River Avon in the town of Stratford-upon-Avon in the English county of Warwickshire. Stratford-upon-Avon chain ferry:  The vessel used on the service is named "Malvolio", after the character of the same name in William Shakespeare's comedy Twelfth Night. Malvolio: Malvolio is the steward of Olivia's household in William Shakespeare's comedy "Twelfth Night, or What You Will". Malvolio:  He is often portrayed as the main antagonist.
River Avon