Bloodborne DLC - Living Failures
A boss from "The Old Hunters" DLC
This one seemed pretty easy as long as you keep the enemies separated and focus down ones that are alone.
Make sure you are paying attention to their spells, particularly the obvious one that makes you think you are all of the sudden in outer space. I didn't know what it was at first and almost died.
Try and find ones to swing at you from a safe distance and shoot them for a visceral attack. It seems that the amount of them does not stop, there will always be more the lower their HP, but once you fully deplete the boss HP bar, all of the remaining ones die.