What exactly is this?

While walking to a derm appointment I managed walk behind this. It wasn't so much a mullet, as it was 2 hair styles. It was like a short, mom-like blonde bob and then long straight dark hair underneath. I won't judge because I did have that incident in the 6th grade when I may or may not have shaved the underneath of my hair. Let's not get into that, its still a sore subject. But I've grown, and I learned that that was not appropriate. This chick was in her 20's and should know better.