Board Thread:Questions and Answers/@comment-28125426-20180527023004/@comment-918732-20180604205207

Out of the four DC/Hanna Barbara crossover comics published last Wednesday, three of them happened on a "Crossover Earth" where the DC and HB characters coexist, and one of them was an inter-dimensional crossover with the HB character travelling to Earth Prime, and then the DC character returning the favor.

Which one was the inter-dimensional crossover?

(This refers to the main story in each issue only, back-up stories are ignored.)