So while attempting bootcamp, my computer crashed and created a ghost partition that refused to be fixed by Disk Utility. Specifically, while attempting to fix the problem, I kept running into
The provided Core Storage logical volume has an incorrect size; you should run whole-disk repair
particularly when trying to use Disk Utility to delete the new free space partition that had popped up, even in recovery mode. However, running*
diskutil repairDisk disk0
and then going through Disk Utility to delete the free space partition re-absorbed it into Macintosh HD. Yay?
*doing a backup before this would probably have been wise.