### Clue: Tyrannical leader usurps king in horrific chamber piece (7)
### Answer: MACBETH 
 ### Explanation: Definition: piece
  T(initial letter,leader of "tyrannical" ***replacing***(usurps) "r"(abbrev. for Rex in Latin,king) in **anagram of**(horrific) "chamber".
Answer:  A play,piece by Shakespeare.  Another WIWD clue as the clue describes Macbeth's deed.