It's possible you're referring to a fan-made concept or a specific story that isn't widely known. To provide more information, I need more context.
Could you tell me:
* What makes you think of this concept? Did you see a fan art, a story, or hear about it from someone?
* What do you imagine "Superman Berserko" to be like? Are you picturing a Superman with uncontrolled rage, a dark transformation, or something else entirely?
With more information, I can help you understand what you're looking for or clarify what "Superman Berserko" might mean in your context.