Patient Zero: Joe Chill turns out to have been the first person to be infected by the Joker virus. This causes Batman to realize that Joker knows he is Bruce Wayne. The escaped prisoners from Arkham arrive at a restaurant and another inmate tells her story. She lived happily with her husband and three kids but one day her husband came from work different. She believed a machine had replaced him and was doing the same to her children. So one day she killed them and removed the chips from their brains. The doctors said there were no chips, but she believed it was all a conspiracy. Later on, the Joker appeared on her cell and showed her he was a machine and was responsible for replacing people all over the city. Suddenly the glass from the restaurant is shattered by people intoxicated with the Joker toxin. Batman(2011) #37 Image from Fandom Zalben, Alex; Horowitz, Josh (April 12, 2015). "Marvel's Movie Future: Here's Everything You Need to Know Through... Phase 4?". MTV. Archived from the original on April 15, 2015 . Retrieved April 12, 2015.

Ax-Crazy: The Joker is at his most unhinged in this storyline, as he engineers a plague that turns almost every Gothamite and the Justice League into monsters as insane as himself. He even grabs an axe in Issue 37 when he's going out of his way to give Gordon nightmares. Kroll, Justin (September 12, 2017). " Star Wars: Episode IX Release Date Moves to December 2019". Variety. Archived from the original on September 12, 2017 . Retrieved September 13, 2017. Oscars: The Complete Winners List". The Hollywood Reporter. February 9, 2020. Archived from the original on February 10, 2020 . Retrieved April 25, 2022. Immortality Inducer: As described in Issue 38, the substances that are in the Lazarus Pits, Vandal Savage, and the Joker are identified by Dr. Paul Dekker as "Dionesium", with each user having come across it and used it differently. As revealed in Issue 39, this substance is also in the electrum given to the Talons of the Court of Owls, though both it and the version Ra's uses are mentioned to be corrupted versions of it, impure by comparison to what Vandal and the Joker were infected with. Lussier, Germain (June 26, 2018). " The Avengers 4 Trailers Are Going to Have a Weird Marketing Problem". Gizmodo. Archived from the original on June 26, 2018 . Retrieved June 26, 2018.Slasher Smile: The Joker, and everyone affected by his newest toxin, default to a manic grin as their standard facial expression.

Knight, Rosie (April 25, 2019). "What's Up with Banner and Hulk in Avengers: Endgame?". Nerdist Industries. Archived from the original on April 26, 2019 . Retrieved April 26, 2019. Goslin, Austen (December 7, 2018). " Avengers: Endgame 's Title Ties Together a Long-Running Avengers Theme". Polygon. Archived from the original on December 7, 2018 . Retrieved December 10, 2018. Chitwood, Adam (May 6, 2019). " Avengers: Endgame: Here's Why Katherine Langford's Big Scene Was Cut". Collider. Archived from the original on May 6, 2019 . Retrieved May 6, 2019. Trumbore, Dave (January 11, 2018). " Avengers 4 Wraps Filming as the Russo Brothers Move into Post-Production". Collider. Archived from the original on January 12, 2018 . Retrieved January 11, 2018.Batman and the Joker are enemies unlike any other. Batman has fought the Clown Prince of Crime countless times, the two forming a dark relationship over the years, and they've gone beyond simple rivals to represent a dichotomy, two sides to the same coin. In the 2015 story, "Endgame." by Scott Snyder, Greg Capullo, Danny Miki, and FCO Plascencia, the turbulent relationship between Batman and the Joker comes to a violent head in a story that could've been a perfect capstone to their endless rival Gotham City is overrun by Jokerized victims, and The Joker himself is prowling the streets. Even as Batman confronts the Clown Prince of Crime, ordinary citizens and Arkham inmates must confront the mark