This isn't the first time I've seen this, in fact it always seems to result in the same outcome: multiple users appear, one posts a bad post, the other edits it until they've got enough reputation to get in chat, and then "fun" ensues:
Since people can accept edits against their own posts and these result in instant reputation, you can easily submit multiple edits in quick succession to get from 1 reputation to the 20 required to chat.
We need a change to the way self accepting edits against your own posts work to combat this, or a rate limit on new users submitting edits, or a rate limit on new users accepting edits... just... something.
Solutions?