Before the era of Superhero Cinematic Universes, there was the time of Superhero Animated Universes. On Marvel’s side, there was Spider-Man: The Animated Series and X-Men: The Animated Series, which were going head-to-head against DC’s Superman: The Animated Series and Batman: The Animated Series. These two franchises have been butting heads with each other ever since they were exclusively publishing comic books and some things never change.
John Semper’s Spider-Man: The Animated Series
When the Spider-Man and Batman shows were being released, it would seem that the creators of the two were in quite a public disagreement with each other. John Semper, who wrote the former, actually ended up shooting some shots at Bruce Timm, the creator of the latter.

All the disagreement seemed to stem from vampires and things got quite bloody.

The Great Vampire War Between Spider-Man And Batman

When Bruce Timm was creating Batman: The Animated Series, he desperately wanted to have an arc where the Caped Crusader would get turned into a vampire. However, such a storyline was denied by the studio as they believed it to be far too graphic for their younger audiences. This resulted in quite a lot of back-and-forth, which was to no avail and the storyline never made it into the series.
Bruce Timm’s Batman: The Animated Series
However, on the other side of the river, Marvel was able to have a vampire in their hit series, Spider-Man: The Animated Series in the form of Morbius. The final authority on what goes into children’s shows is the Broadcast Standards and Practices Department.

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The way that series writer, John Semper was able to get around the ‘no graphic vampires’ rule was by changing how Morbius feeds on his victims, making the character feed through suction cups in his hands.

Bruce Timm and John Semper Threw Shade At Each Other

John Semper seemed to have been smug about what happened. He addressed both his win against the Broadcast Standards and Practices Department, as well as Bruce Timm during an interview. Speaking to DRG4 in an interview, he talked about how he had an excellent relationship with the department when he was making the series, which made it easy for him to do what he wanted.

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Morbius in Spider-Man: The Animated Series
He then made some shots at Batman: The Animated Series, talking about how fighting with the Broadcast Standards and Practices Department was not a very wise thing to do. He believed it to hamper creativity and make them unproductive, seemingly making a shot at the series and its creators.

“[“Spider-Man: TAS”] did that really lame one right? He had like suction cups on his hands? So that was fine. Like if I wasn’t going to do it properly, I wasn’t going to do it.” Bruce Timm said about what Semper said.

Bruce Timm’s Batman: The Animated Series
As a response, Timm talked to ScienceFiction.com, stating that he would rather fight for his creative vision rather than bend over and make something he did not believe in. It is safe to say that the entire situation got quite heated.