So, I'm solidly in the midst of my Gatecrashing campaign (I just got my first PC fatality last session! Whoo! And it was hilarious.) and I'm in the process of designing my next scenario to put my PCs through. And, thanks to being a detail-oriented, fastidious GM, I'm currently stuck on an aspect of my next planet design: Oxygen. Specifically, how much oxygen is too much oxygen? If the atmospheric pressure is in the range of 3 bar, with a carbon-based biosphere on a habitable moon, at what point does the atmosphere itself become a spontaneous combustion risk, from lightning strikes, if nothing else? And would it be breathable by any sort of biomorph at those pressures?
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -Benjamin Franklin