Chronos takes on Superman and Batman in World’s Finest 321 (Nov. 85), in a story by Cavalieri, Delbo and Alcala.
Chronos had appeared in brief scenes in the previous two issues,being contacted by the Power Broker,a mysterious villain,whose identity and motivation never did wind up getting revealed. Chronos had last appeared a couple of years earlier in Justice League of America.
Chronos draws out Superman and Batman, and then sends Superman racing into the past, to prevent bombs Chronos has sent there from changing history. But that is just to get Superman out of the way.
His real target is Batman, and Chronos sends him back in time, to the moment of his parents murder. Chronos figures that Batman will either be so traumatized by seeing this it will break him, or he will step in to prevent it, thus erasing his own existence. Not a bad idea, but it fails. Batman watches, and that’s all.
The heroes make it back to the present, and Chronos runs off. The story gives a weird set-up for something more with his character, but in fact, his next appearance is in the pages of Crisis on Infinite Earths.