How is he when the lights are off?
Have you tried playing look at that with the lights with him?
My boy will decide that random objects are scary for whatever reason but usually he'll work up enough courage to creep up to whatever it is, plant his back legs once he's within sniffing range, creep forward on his front paws, then stretch his neck out as far as it will go and sniff at the object. If i can figure out what's causing his alarm, like today he for some reason got alarmed by my shirt (while I was wearing it

) I try to encourage his investigation and show him that it's not scary, other times I can't figure out what his problem is.
So far he has never become scared of Christmas decorations but it would not shock me if he did. One time he decided that a tassel on my rag rug was scary, the rug have been there on the floor for months and had never alarmed him before.