Pillars of Eternity was moddable only because it was written in C# (Unity iirc), making it possible (though not straightforward) to more or less modify the code however you want. So a mod was essentially a bunch of overwritten classes.
A game that you could literally just fork on GitHub and change things would certainly be moddable in a sense... Handling multiple mods without conflicts, however, is another thing. For that you need a proper modding interface, like the original Baldur's Gate or Skyrim.
I heard it snarl before I saw it. It was chasing a deer, noticed me, stopped and just sat there staring at me about 50 yds away across a little valley, not menacing towards me, more curious. I put my hands on my head to try to "look big". After a while of us staring at each other, I lost my nerve and backed away and then sprinted away towards a nearby street. It didn't chase. Based on the ease with which it leaped up that hill after the deer, it obviously could have caught me if it wanted to. Funnily enough I met someone else on the trail just afterwards, told him there was a mountain lion, and he was like "where?"and ran towards where I saw it... This was in southern California.