Home brew questions, fermenting kombucha

The following questions are one we have fielded over ten years of assisting folks in their home brewing kombucha.

Why is my SCOBY so ugly?

My SCOBY doesn't look like any I've seen before.

I've never seen a SCOBY before, what do I look for?

What is the range of normal appearance for my SCOBY?

What is a SCOBY and how does it grow?