I’ve run across a story that tells us, this smells bad. It smells bad to prey animals, such as the one we are descended from and which we not not entirely changed from.
This is something you could use in your fanasy RPG. Let’s say the party is heading down a corridor when they pick up a bad smell. There’s blood in the area, and it tells those who do pay attention there is something wrong nearby.
You could even use it as warning, for who knows who might pick up the scent and come hunting? Orcs, goblins, even Klingons might come prowling around looking for a meal.
Fighter: Don’t worry about my gash, we have treasure to find.
Cleric: Shut your yap. I don’t want the local goblins to come looking for you to nosh.