wish
Explanation
The Joke
A couple sees a shooting star. One says "Sally! A shooting star! Make a wish!" Sally starts to make a wish, but then notices the shooting star is turning — "it's coming right at us." She then quickly says "Only change the wish! Change the wish!" before the meteor impacts with a "BOOM."
The Humor
The comic plays on the childhood tradition of wishing on a shooting star. The twist is that what appears to be a harmless distant meteor is actually an incoming impact event. The humor comes from the desperate, panicked attempt to change the wish at the last second — as if the wish-granting mechanism is some kind of rigid bureaucratic system that processed the original wish too quickly. The implication is that Sally's original wish may have inadvertently been for the meteor to come closer, or more darkly, that no wish can save them now. The joke works through the absurd contrast between the whimsical innocence of wishing on stars and the catastrophic reality of an actual meteor strike.