It went like this:
Me: These Duplos have eyes all over them. It’s like a creature from Revelation.
He: What’s Revelation?
Me: It’s a book in the Bible. There are all sorts of creatures in it. Dragons, too. It will be a great book for you to read sometime, maybe when you are older.
Me: It’s a little bit scary.
He: Is there a movie?
Well, yes, son, there is a movie. Quite a lot of them, in fact. But we’ll start with the book first.
He’s started on chapter books with us, though, so we’ve been able to begin tackling some fun stories, like this. Revelation, perhaps, later.