Clue: What does one get when one crosses an angry jackal with an eccentric mouse — 7? (1,7,4)
Answer: A MUSICAL JOKE
Explanation: Definition: 7?
="7?" – a loose [mis]interpretation of 'OPERA COMIQUE'; and the surface is set up as a JOKE
 *A Musical Joke* is also the name of a satirical/comedic composition by Mozart 
 **I**="one", inside (jackal)* with (mouse)