While DC's Joker may be known for his deadly practical jokes, he fell victim to a horrible prank. Joker: Last Laugh #4 puts the titular villain on the brink of death, causing him to work on some bucket list tasks. What turned into a horrible time for the world, however, was really just the result of a sick joke directed towards the Joker.
The Joker has pulled some massive schemes on Gotham, but being on the brink of death escalated his efforts against the world. He wanted to seek revenge on then-president, Lex Luthor, as well as gain an heir to continue his work. These many bucket list schemes put his laughing fish and other jokes to shame. Yet the worst joke would be discovered by Black Canary—and it was actually for Joker's own good.
Joker: Last Laugh #4 has the creative team of Chuck Dixon, Scott Beatty, Andy Kuhn, Tom McCraw, and Willie Schubert. Within the issue, Black Canary confronts Dr. Clyde, a doctor who provided Joker with CAT scans revealing a brain tumor. She discovers quickly that this is the doctor's idea of a sick joke. He altered the CAT scans and told the Joker about the condition as a means of turning Joker's own sick jokes against him. The Joker's life isn't actually medically threatened, despite being told otherwise.
The Joker may be evil, but this prank is definitely one of the worst that DC has pulled. While some may argue that the Clown Prince of Crime deserves it due to his long-list of evil over the years, this seems like a very drastic action to take. Skewing anyone's medical results is wrong, especially when administering treatment to patients who are definitely not in the best mental states. The worse part of all is that Joker's schemes and actions within this comic series could have been easily avoided had the doctor just been honest instead of seeking revenge on the iconic Batman villain. Without these image alterations, the Joker still would have been locked up in the Slab, watched closely by Oracle and the penitentiary's staff. While the Joker often breaks out of prisons and Arkham Asylum, he wouldn't have had as much reason to make such a show of it.
With his life on the line, the Joker used Joker venom on his fellow inmates to assist his breakout and recruited them to help him wreak havoc on the world. Instead of limiting himself to Gotham, he goes beyond the city limits. He becomes a global terrorist of sorts with no reason to back down or ease up his efforts. There are no consequences awaiting him if he is just going to die because of a tumor. Although the Bat-Family is able to eventually stop the Joker, this sick, dark joke certainly took its toll. With many dead unnecessarily and the Joker operating unhinged, this practical joke was one of DC's most destructive and evil.