Red Kryptonite is a fictional substance from the Superman comic book universe. Unlike regular Kryptonite, which weakens Superman, red Kryptonite causes unpredictable effects on him, often altering his personality or abilities temporarily. The effects of red Kryptonite can vary widely, leading to humorous or chaotic situations. For example, it might make Superman act irrationally or develop unusual powers. This unique characteristic makes red Kryptonite a popular plot device in various DC Comics stories, adding complexity to Superman's character and adventures.