I would pour off the black stuff and feed it....and leave it on the counter....if it comes to life, it's good....but be aware it could be dead. I know you can dry starter and the dried starter will grow again once it's fed....but this was not dried.
Anyhow....feed it...if it bubbles it's alive and fine......but don't get your hopes up!!

The black and smell comes from fermentation (alcohol). If there's a part in the center that's merely grayish or putty colored (i.e., short on starch to eat but still intact), it could well be still alive. What we can see in the picture on the bottom of the jar doesn't look dead, though it could be. It may well just be dormant. Throw away anything that's actually black or looks like mold (I don't see mold in the photos). Be gentle with it if you want to revive it.

Put it in a clean glass measuring cup or dish and stir half its weight in room temperature water. Look for tiny bubbles. Bubbles mean life. If there's even one sort of bubble it might be alive. Add the same weight as the water in flour, one spoon at a time, and stir well. Let it sit on the counter overnight, at least. If you can see bubbles in the sides of the dish and/or an increase in volume, it's alive. Feed it again once you see plenty of bubbles but don't discard. Twelve hours later, discard half by weight and feed again, half the remaining weight in flour and half water, so each feeding you're feeding it its own weight again. Keep discarding and feeding every twelve hours for a week.

By then, the volume should double between feedings. If it doesn't double but does rise, keep up the feeding. If it doubles by eight hours and holds its volume for twelve, it's very strong and ready to go back in the fridge if you're not going to bake. If, assuming a kitchen at 68° F or higher, it doubles within twelve hours but not until the end, or if it sinks after doubling, the yeast is mostly strong but the flour isn't. Try kneading just a little with your spoon as you feed.

Silver lining: If you can rescue the starter, it should be strong. Survival of the fittest and all. :)

It's been a while... to feed would I just use, say, 3 oz flour and 3 oz water?

I now see plllog's directions so will follow that. Thanks!

I edited a little, for what I hope is clarity. Good luck!

Keep us posted. I dont eat bread much, but I love sourdough. Would be handy for me to know if I should start making my own, and it sits between loaves.

Here’s an update: a bubble or two appeared after about 12 hours, and now after about 40 hours (one feeding, no discard, just sitting on covered with light towel counter) there are several (see pics). So I guess it’s alive! Overnight the little layer of dark separation that you see formed. I’m thinking I’ll try to pour that off and feed, without discard, as per @pilllog’s suggestion. Also, it still smells quite strong. Volume didn’t increase in the 40 hours.

@artemis_ma: i don’t suggest waiting 1-1/2 yrs between loaves!!

LOL, arlo 48! But it will probably be three or four months...

Well either it's alive...or you have started another batch!

I would start a new one. That one looks like a science experiment run amok. The black could be mold.

The gray liquid is "hooch". It's fine. It's alcohol. That's more evidence of yeast conversion. It looks hungry. Feeding it is definitely the way to go, but you're going to have to discard soon.

I just did the second feed, without discarding. Next time I will discard. Thanks!

Wow, this is cool! It looks totally happy. And volume increased by about 33% in 12 hours. I will now start the discard/feed process.

Wow~!!

It's ALIVE!!

So happy to hear it was as salvageable as it looked. :) I think you'll find it will also be stronger than when you first hatched it. :)

Congratulations!