Complex sentence: The Joker is quickly intercepted by the Batman and apparently dies when he falls into a river and is electrocuted by his super-charged joy buzzers, while the Penguin takes the opportunity to enter the cemetery himself.
Split into simpler sentences: The Joker is quickly intercepted by the Batman, after which he is apparently killed when he falls into a river and is electrocuted by his super-charged joy buzzers. The Penguin takes the opportunity to enter the cemetery himself.