Remember the disgusting, voracious insectile aliens from the "Alien" movies -- and how their blood was a kind of corrosive slime that burned holes into whatever it touched? Turns out that -- well, I'm getting ahead of myself. Let me answer the question in my title. What I'm researching right now: Caves.
Here's the wildest info I've come across. Just within the last two decades, speleologists (cave scientists) have discovered a new form of life in some very unusual caves. There are a few caves with a highly sulfuric ecosystem -- the sulfuric acid is so concentrated, in fact, that it's close to battery acid. Cavers have to wear protective clothing to keep from being burned, and respirators so they aren't killed by poisonous sulfur gas. (What nervous twitches the families of these scientists must have!)
So, we have a highly toxic environment in these caves, too toxic for most known life forms. And yet there are microbes that dwell and thrive in these conditions. Generically they are called extremophiles. Some of these microbes form a kind of slimy matrix to live in, and threads of this slime hang like rubbery stalactites from the walls and ceilings. Called "snotties" (for obvious reasons) these microbes are giving scientists some new clues to possible life beyond our earthly boundary. Talk about thinking outside the box.
So, what am I doing with this information? I don't know yet. That's the great thing about being a writer. I'm just following an intriguing trail to see where it takes me. At the moment my trail is leading me deep into a rather terrifying cave. If I don't make it back out ... send help!