What do you think is a joke that can be told for a lifetime?

I laughed so deeply at school. There was a class at that time, and a butterfly flew into the classroom. The students all whispered, butterfly, butterfly. Then our head teacher suddenly stopped teaching and went after butterflies. He really chased butterflies around the classroom and said, come on, come on, fly to me and stop in my palm. Our head teacher is an old man in his forties, wearing a very serious white shirt all the year round.