If you think about it, Spider-Carnage in the 90s animated series finale could have been the precursor to The Batman Who Laughs, if you count Carnage as Marvel's closest equivalent to the Joker and Spider-Man as a stand-in for Batman. Both of them turned out to be the central villains of a Multiverse-spanning plot that included alternate-reality variants of themselves, even if Spider-Carnage's variants were heroes and The Batman Who Laughs' variants were villains, barring the "main" Batman. Then there's the fact that the Dark Knights of the Dark Multiverse were brought together by an interdimensional patron, which is rather similar to the Spider-Men of the Multiverse coming together thanks to Madame Web, who in the animated series was an interdimensional guide and mentor to the "main" Spider-Man. Of course, the main difference was that The Batman Who Laughs ultimately wanted to remake the Multiverse in his own twisted image, whereas Spider-Carnage simply wanted to annihilate the Multiverse, "even if I have to do it one dimension at a time."