Clue: Gloomy character's blowing top over drugs and monstrosities (8)
Answer: EYESORES
Explanation: Definition: monstrosities

(e)**EYORE'S** ("gloomy character's") [*blowing top*, i.e. first letter) *over* **Es** (ecstasy, so "drugs")
 

 
*Eeyore is the rather depressed donkey in the Winnie the Pooh stories