Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

The Joke

A man stands in what appears to be a Halloween setting (with small trick-or-treaters and a ghost visible in the background) and announces, "I'm a time traveler from the post-apocalyptic present." The caption below reads: "It's getting easier and easier to dress for Halloween."

The joke plays on the idea that modern life has become so chaotic, stressful, and dystopian that you no longer need an elaborate costume to be something scary for Halloween. The man is not wearing a costume at all -- he is simply himself, a person living in the present day, and that is horrifying enough to count. The "post-apocalyptic present" is a darkly humorous oxymoron suggesting that the apocalypse has already happened and we are living in it.

The Humor

The comic derives its humor from the bleak observation that contemporary reality has become indistinguishable from dystopian fiction. The visual reinforces this: the man is wearing a plain t-shirt with no costume, standing among actual costumed children, and his "costume" is simply the truth. It is a concise bit of gallows humor that taps into the widespread cultural feeling -- particularly prevalent in 2018 -- that the modern world is increasingly resembling a post-apocalyptic scenario, making traditional Halloween horror feel redundant.