This means, as I understand it, that teeth evolved from A MOUTHFUL OF EELS! Holy crap that is so 4chan it's scary. Here is the picture I get from that:
There's this big jawless fish, probably survives by eating krill like a whale. And it gets infested with remoras! And they get on it so bad that they get in the jawless whale's MOUTH, and the the whale can't do anything about it, so it swims around for its whole entire life with a mouth full of boned leeches, and as time goes by these leeches learn to thrash their tails around whenever there's food in the whale's mouth, so that it can eat bigger things.
So when this giant whale eats you, there are a bunch of razor-sharp leeches in there that will chop you up. As if getting swallowed by a whale wasn't bad enough.
And this went on for so long that the eels got smaller and smaller and harder and sharper and grew more to the right spots...and, just like mitochondria, were eventually incorporated into our body structure and even DNA.
In other news, it's been a marvelous day so far.