Did Malcolm play a practical joke on macduff?

Yes, Malcolm did play a practical joke on Macduff, but it was not meant to be malicious. In Act 4, Scene 3 of Shakespeare's "Macbeth," Malcolm pretends to be unfit to rule, describing his own vices and shortcomings to test Macduff's loyalty and resolve. This ruse is a way for Malcolm to determine whether Macduff is truly committed to the cause of overthrowing Macbeth and restoring Scotland. Ultimately, it shows Malcolm's cautious nature and his need to ensure he can trust Macduff.