Bacterial Corrosion
Is this some sort of high school science project that we’re not familiar with? Are people supposed to grow mold and other gross things in their cars now? The answer is none of the above. The mechanic claimed that it was metal corrosion, which is unlike anything we’ve seen before in our lives.
How this thing came about and how long it’s been there, perhaps we’ll never know. And we’re pretty thankful for the fact that we don’t have to deal with this sort of grossness on a daily basis. But why is this metal corrosion growing on what appears to be fabric? Some answers aren’t worth searching for.