These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Mario Bros.
Demonic Spiders: The green fireballs, which spawned not from the pipes, but directly on your current floor.
Ear Worm: The opening snippet of "Eine Kleine Nachtmusik", a classic Mozart song.