@rsynnott And the crazy thing is, the mastodon.social guys 'solved' it by closing registrations for a bit.
May not the best solution, but something to plug the gap until a better solution is found/created.
At least other servers are able to temporaily defederate from .social until its fixed.
Crazy to think that this is the 2nd spam bot that I have seen since November. And I have about 20+ on my (now) inactive Twitter.