I wonder if this was a test of Casper that went rouge lol. Actually if the network wqs on POS right now it would have haulted because miners can keep up with this where as virtual miners dependent on nodes IO speeds would not so its good this happened prior to serenity.
Comments
https://m.reddit.com/r/ethereum/comments/59vhws/update_on_imminent_hard_fork_10282016/