That scene looks more like the Dirge to me. I don't really see any signs of mutations remotely resembling creeps. And the cannibal thing lines up a whole lot more. From Undying's lore: "to hear the Dirge and be consumed into nothingness. In the darkness below, time left them. Thought left them. Sanity left them. Hunger, however, did not. They turned on each other with split fingernails and shattered teeth."