These shoulder pads are from the Forge World conversion kit for plague marines. The observant will notice that they contain three embedded spheres, each of which has holes in them. They seem to be poking out of the shoulder pad, causing cracks where they protrude.
My question for today is this: what are they?!?! I've seen them on other Death Guard related miniatures, such as Typhus, but I'm just not sure what they're supposed to be? Nests for the destroyer hive critters? Or something else? Opinions welcome!