Trust Me! (1954)

Max, an illusionist as unlucky as he is skilled, would like to marry his boss's daughter, but his boss won't hear of marriage and even threatens to fire him if he doesn't come up with an interesting act. A supplier of magic items comes to Marx's rescue, handing over his "magic clock". Marx locks himself in to experiment with it and, unable to get out, falls asleep... He has a dream in which, with the power to make false things true, he becomes the hero of extraordinary adventures that take him to an Eastern country where he is made Emperor. He calls Helen to marry him, but the deposed Emperor takes revenge by having the usurper locked up in a sarcophagus.

Unfortunately the movie Trust Me! is not yet available on HBO Max.