Possible Clues:

• 'Horton Hears --'
• "Horton Hears ___"
• Dr. Seuss title ender
• What kid lit's Horton hears
• 'Horton Hears '
• Dr. Seuss' 'Horton Hears __'
• 'Horton Hears —!'
• Seuss' ''Horton Hears __''
• Dr. Seuss' "Horton Hears ___"
• 'Horton Hears ___!' (Dr. Seuss book)