Let’s say your teenager acquires a huge wooden plaque adorned with enormous animal horns. And he decides, “These horns would make a great Viking hat.” Then, he goes to an army surplus store and explains why he needs a helmet. Then he borrows an electric saw from the nice new neighbors.
You’re thinking, Jesus Christ, this will never work, why can’t he see that?!”
The thing to do is stand back and let fate take over. They’re going to do what they’re going to do, and it might end up with a gigantic Viking helmet.