Watch Superman the Animated Series Knight time
In "Knight Time", Bruce Wayne has disappeared and Superman must help Robin find him by pretending to be Batman. Superman takes on the role of Batman in a way that involves more than just putting on the costume of the Caped Crusader. Superman takes on Batman's role as "detective". The plotting of the episode is excellent. It moves at quick pace and does not let up. It features two truly great action sequences: when Superman as Batman fights Bane and when Superman as Batman confronts Brainiac. The animation of these sequences is wonderful.
The teleplay builds up an interesting relationship between Superman and Robin that is sharp contrast to the relationship between Batman and Robin. Superman is much more easy-going and friendly. He jokes around and interacts with Robin more as a friend than as a mentor. Batman, of course, rarely jokes around and is often much more serious. Of course, Superman's relationship with Robin is more than just friendship. Superman actually a lot of respect for Batman's younger partner. Appropriately the teleplay also emphases the differences in the crime-fighting styles of Superman and Batman. This comes out best in the scene featuring the Penguin. When the Penguin refuses to offer any information on the whereabouts of the Mad Hatter, Superman who is pretending to be Batman is stumped. He appeals to the Penguin's sense of humanity, but the Penguin still refuses to talk. After Robin tells him to kick over a desk and he does so, the Penguin talks. It is interesting to speculate how that scene would have been like if Superman were confronting the Penguin as Superman. Would Superman have kicked over the desk? Would the Penguin have talked without a show of force?
One can of course ask whether this episode makes Batman look weak? After all, Superman handles Bane who is Batman's most physically powerful villain without any trouble at all. Bruce Wayne is also clearly outclassed and enslaved by Brainiac. Superman must rescue him. All in all, however, I don't think that the episode makes Batman look weak. Batman's strong points are his cleverness and ingenuity. Brianiac who takes control of Bruce Wayne in virtue of a cleverly placed pinprick does not test these merits. Of course it is true that a Superman villain gets the better of Batman. Later on in the series, however, in the episode "The Demon Reborn" a Batman villain named Ra's Al Ghul gets the better of Superman. Though Batman has to be saved by Superman in "Knight Time", Superman needs to be saved by Batman in that episode. So, in the end Batman is around to return the favor.