Where the Justice league enter amity park for any reason ( for example government list phantom a threat, they discovered all the declined help request from amity, etc). But in the end due to Batman or some other Justice league viewing phantom as dangerous they act on it leading to a confrontation with not only all of amity park (even Vlad) who didn’t want the heros that never came to help them but also with phantom who summons from the infinite realms there dead parents or those close to them who have passed. Like Superman would get his parents plus maybe some extra kyrptonians, Diana would get Pandora, and Batman would get his parents.
Extra: All the dead parents especially Batman’s parents when Batman views and acts like phantom is a threat is just the parent equivalent of ‘im not mad I’m just disappointed in you’ look/conversation.
For comedic value the batfam is also there watching batman be berated by his dead parents (Jason is rolling with laughter at Martha Wayne just grilling Bruce/ Martha meets the batfam and goes awww grand-babies)
@punkeydoodles makes some of my favourite short animations on social media at the moment. You should look them up, especially if you like D&D content too.