Possible Clues:

• Elphaba Thropp, by another name
• Film villain who never said 23-Across, with 'the'
• Awesome speller?
• Dream analogue of Almira Gulch
• "The Wizard of Oz" villain
• Green-skinned movie villain
• One of two figures in 'The Wizard of Oz'
• Oz character
• Western villain?
• "I'm melting!" proclaimer