Punch newspaper when a pen becomes a piper
I think there may be a bit of a misunderstanding here!
A pen cannot become a piper, as they are two very different objects with different functions. A pen is a writing instrument used to apply ink to paper, while a piper is a person who plays the pipes, a musical instrument.
Additionally, the phrase "when a pen becomes a piper" doesn't make sense, as it's not possible for a pen to transform into a piper.
If you meant to ask about a different topic or scenario, please feel free to rephrase your question, and I'll do my best to help!