An errant mealiemoth got into a batch of starter and probably died a fairly painless death, considering the fermentation. So, I discarded it, washed the pitcher, soaked it with boiling water for a bit and started a new one. Because of the mealie, I covered it with punctured foil instead of the clay lid, which leaves a gap near the spout. For a couple of days I tended to it, but got busy with other ferments like mead and cheese and forgot about it, relying on my other starter for bread.
No big deal, I thought. Just feed it and it'll do its thing, right? Oh so wrong. I pulled off the foil only to find the starter looking a bit oddly yellowish, but the wall of the pitcher was coated in a wicked dark gray mold. The odor was horrible. Some unfriendly got in there and went to town. I was so appalled I didn't even think to photograph it to share and scare before dumping it down the drain.
In retrospect, the mess could have been prevented by tending properly to the baby starter. It needed time and food to grow a good pH, but my negligence ended in a wasteful mess. For shame.