the-definition-of-unlife
Explanation
The Joke
A child tells their grandfather they do not like the word "undead" because it is chauvinistic. They argue that the undead can move, communicate, think, have DNA, are made of hydrocarbons, and create entropy. They are just a form of life that happens to look similar to dead humans, so they should be categorized as "not alive and not dead." The grandfather counters: if the criterion for "undead" is just "alive but looks dead," then they should call anyone over 60 "undead." The child adds that one quality of life is the ability to reproduce, and zombies, vampires, and mummies cannot do that. The grandfather retorts: "Oh my god, this is true of old people too." When the child asks if the grandfather is saying he is undead, he replies: "Technically only Grandma is undead."
The Humor
The comic takes a philosophical and taxonomic approach to the concept of the "undead" and uses rigorous biological definitions to reach an absurd conclusion: that elderly people meet the same criteria as zombies and vampires. The child starts with a seemingly progressive argument about not using the term "undead" because it is chauvinistic toward a form of life, but the grandfather hijacks the logic to show that if you define "undead" by appearance (looks dead but is alive) and inability to reproduce, then old people qualify. The final punchline -- that only Grandma is undead -- adds a layer of dark marital humor, implying she is either particularly decrepit or, more likely, that the grandfather is making a joke about their lack of intimacy.