gotham
Explanation
The Joke
The comic retells the classic Batman origin story. In Gotham City, a mugger shoots a couple in front of their young son, who cries "Mom! Dad!" and vows "I will avenge this! I will be a force for justice in this town!" But the mugger, still present, says "It's okay, I'm fine, they didn't hit anything vital -- wait, my cigar! It's cracked!" The mugger's companion adds "Me too!" The young Bruce Wayne then says "Oh well, that's not very dramatic."
Forty years later, a grown-up version of the boy is shown as a wealthy socialite at a charity event, saying "Another gin and tonic, Master Bruce?" He replies: "My life is pointless."
The Humor
The joke completely undermines the Batman origin story by having the mugging go wrong in the opposite direction -- instead of the parents dying tragically, nobody of consequence is seriously hurt, and the only real casualty is the mugger's cigar. Without the formative trauma of witnessing his parents' murder, Bruce Wayne never becomes Batman. Instead, he grows up to be exactly the aimless, bored billionaire that Batman's alter ego only pretends to be. The punchline -- "My life is pointless" -- is darkly funny because it suggests that without personal tragedy as motivation, even the most privileged life feels empty. It is a commentary on how superhero origin stories require suffering to give purpose, and that without it, wealth alone leads to existential malaise.
References
This is a parody of the origin story of Batman (Bruce Wayne), created by Bob Kane and Bill Finger. In the canonical DC Comics version, young Bruce Wayne witnesses the murder of his parents Thomas and Martha Wayne by a mugger (often identified as Joe Chill) in Crime Alley, Gotham City. This traumatic event drives Bruce to dedicate his life to fighting crime as Batman.