One or more corpses, and a bunch of clues that tell the story.
Do We Have This One?? It seems like it should exist, but I haven't found it.
Occasionally in fiction, corpses appear. Most times, their deaths are shown, or at least hinted at. Sometimes, the cause of death is left a mystery. Sometimes, it's up to a character in the work to tell the audience how it happened, possibly after deducing it themselves. This trope occurs when the scene of death itself tells the audience how it happened. This can manifest in several ways. The physical injuries on the body itself are a good way to start. Objects scattered around it can elaborate, though this can easily get too silly to be successfully Played for Drama. An easier route is to use an Apocalyptic Log.
This kind of death can be important to the plot, but is just as often thrown in for Black Comedy. In Video Games, it tends to appear as Easter Eggs.
Related to, and can overlap with, Room Full of Crazy and Rube Goldberg Hates Your Guts. Contrast and compare Noodle Implements. As this is a Death Trope, beware of spoilers!