Unseen Force/ Something's Stirring...
So, we all know the infamous "Something's stirring..." message you get when you've been grinding on a floor for too long, followed by the gusts of wind. I don't know if this was already known or said, but in the future dungeons during the main story, when the "Something's stirring..." message pops up, rather than a gust of wind, there is an earthquake of some sort. I was grinding in Sealed Ruin when it happened.
I thought it was just a thing in Sealed Ruin, since it's a cave area, but that same earthquake effect happens in all dungeons (Chasm Cave, Dark Hill, Dusk Forest, etc), which I find really cool since in the future, no wind blows. Though I feel like that earthquake should have been a thing for all cave-like and mountain dungeons in the past rather than the wind. I find it way more threatening.