Is a black coating dangerous when cooking on cast iron? A lot of times when I use my cast iron pan, I'll sometimes get some "black stuff" which I assume is gristle on my food. It doesn't taste bad, it's not a "TON" - I'm assuming it's a combo of burnt+black stuff from the cast iron pan.

Is this in any way dangerous?
Black stuff on a cast iron skillet is most likely just a thin layer of burned food. It's not horribly dangerous (I'm sure you've eaten some charred things before) but it does make your food look worse, so you may as well just keep your skillet clean and well-seasoned and avoid it.