Since the skulls event ended, the Cranial Implant says an enhancement can be completed by eliminating Skull Tithe daemon engines. Used to say Skull Procurators. I got the game in the middle of the event, so I was only able to collect 91 skulls. When the event ended, I was hopeful I could finish by finding these daemon engines, but I have no idea what they are. My highest character is level 40, and I've never seen one.

It's kind of confusing that the item says both!