Clue: Obsession with Paddington? It could merit a hard stare (7)
Answer: BUGBEAR
Explanation: Definition: It could merit a hard stare
 BUG(an obsession/an enthusiastic interest in something) **plus**(with) BEAR(an example of which is Paddington Bear, a fictional character in children's literature).
Defn: "It" being an imaginary character invoked to frighten children/a bogeyman.