I used to be afraid to eat black seeds from watermelon or seeds from an apple. My mom pounded it into my head that I would grow a watermelon patch/apple tree in my stomach
Zombies. I had a rather irrational fear of them. Its silly to me because I knew they didn't exist. Now, I love them. Can't get enough Walking Dead and zombie films.
I used to be terrified of vicars. When I was 7 I threw an encyclopaedia at the local reverend's head. I was a weird kid, who tended to have a severe existential crisis about once a fortnight. It caused stuff like that to happen.
At one point I had a serious fear of bridges. Not **too** silly because risks are risks. And there are decent risks going over a river on an old stone bridge.