A scene, joke, or offhand line that was originally meant to be funny or light-hearted but which, due to traumatic events in future episodes of a show or in real life, now makes the viewer cringe when it is seen in reruns. When someone says that a bit of comedy has been "overtaken by events", this is the trope in play.
This often has to do with a character or actor's death and is named for a line [...] [tvtropes.org]