Dry rot, added @melodynotevintage, spreads to other items so it’s important to isolate the garment and take action immediately. “So one of the first things that you wanna do is…look at the shoe. Look ...

Some commenters thought it might be “some kind of wet rot” or even “mushroom mycelium,” warning that a water leak was almost certainly behind it. Others were more spooked, with one person saying it ...