Dennis Hamley's The War and Freddy. It's WWII, and young Freddy, who is staying with a neighbouring boy, has to endure nightly games after lights out in which he is forced to play the Germans against the neighbour's British, and inevitably to lose (because to win would be unpatriotic). Eventually he gets his own back. Triumph! But then his mother (who's been visiting his sick grandmother) arrives to report that she is dead and that Freddy will be needed at the funeral. End of story.
They all have in common: a) the abrupt and dramatic change of mood, occasioned by an unsignalled piece of news; b) the placing of what has gone up to that point into the perspective of the Really Big Things (birth and death), and c) the Finis before we've really had time to recover. The effect is that even the shaping and sense of proportion we associate with art buckles under the arbitrary impact of fortune's blows: et in Arcadia ego.
Is there a term for this sort of thing? Are there any other examples? Examples from other forms - music, perhaps?