Cooking
Explanation
The Joke
The comic shows a man visiting his dying father in what appears to be a hospital bed. He says: "I know this might be your last birthday we have together, Papa. And it's hard to shop for someone who's dying." He then recalls that his father once gave him "Cooking for 1" as a joke when he had been single for 6 years. The dying father chuckles and says "Ha! I absolutely nailed you that... huh." In the final panel, the son reveals his gift: a book titled "Cooking for Zero" -- a darkly humorous parallel gift implying his father will soon be dead and cooking for nobody at all.
The joke is a perfect act of revenge served cold. The father once mocked his son's loneliness with a pointed cookbook gift; now the son returns the favor with an even darker version of the same joke, turning the father's own gag against him at the worst possible moment.
The Humor
The comedy is pitch-black but structurally elegant. It works because of the perfect symmetry: "Cooking for 1" mocked the son for being alone, and "Cooking for Zero" mocks the father for being about to not exist. The father's reaction -- starting to laugh at his own old joke before trailing off into "huh" as he realizes what is coming -- is expertly paced. The comic also finds humor in the universal awkwardness of gift-giving for someone who is terminally ill, taking the real and uncomfortable question ("what do you get a dying person?") and answering it with savage honesty. Despite the dark subject matter, there is an underlying warmth -- this is clearly a family that expresses love through ruthless teasing.
References
"Cooking for One" is a real genre of cookbooks aimed at single people, often given as tongue-in-cheek gifts. The comic invents "Cooking for Zero" as the logical and morbid extension of this concept.