I have a 3.5 year old, who, admittedly, watches more TV than he should that is suitable for older children. At 2:30am I hear the quiet creaks coming down the hallway floor and a little voice say, "I'm scared. I'm scared of The Joker." My first response was "The Joker isn't real, he's just a character on TV," but I knew this wasn't enough nor was it validating. Children need empathy and a creative reworking of their perceptions and experiences that allows them to perceive a sense of control over a fear. Fortunately I could use his imagination to guide him in managing his fear instead of falling prey to his fear.
Me (adapting a song he has learned at school): "You are so big and strong and mighty. There's nothing your God can't do. He's on your side.
Son: Will he fight the Joker?
Me: He will fight for you and win!
Son: I want the Avengers to put the Joker in jail.
Me: And lock it with a key.
Son: But what if Joker break through the jail?
Me: God will put one of his angels in front of the jail to guard it. He has a big sword.
Son: Are there enough angels to fight the bad guys? Will they circle around them?
Me: Yes the angels are strong and mighty too and will fight to keep you safe. You are safe, strong, and mighty.
This conversation along with some snuggles in bed tamed his worry and he was able to fall back asleep after I left his room. The following article Helping Your Anxious Child Overcome Bedtime Fears gives fantastic ideas for taming a worry brain and moving to a more regulated state. The strategies are not exclusive to bedtime fears. You can find it here.