"You are saved," cried Captain Delano, more and more astonished and pained; "you are saved: what has cast such a shadow upon you?"Herman Melville, Benito Cereno
Harry: I tell you, it is not me you are looking at,
Not me you are grinning at, not me your confidential looks
Incriminate, but that other person, if person,
You thought I was: let your necrophily
Feed upon that carcase…
T.S. Eliot, "The Family Reunion"
First, Benito Cereno is a short novel about a slave rebellion aboard a ship that Melville wrote. Knowing that, we might assume that the "you" is directed to slaves on board. This epigraph offers insight into Ellison's own issues with blacks in post-bellum (post-war) America – although the slaves on board Melville's ship are "saved," they've still got some pretty heavy shadows hanging over them. Similarly, after the American Civil War ended, slavery was abolished and black men were freed, but, as Invisible Man shows, social freedom does not follow from legal freedom.
As for the excerpt from the Eliot verse play, we should get some terms straight first. To start with, necrophily is synonymous with necrophilia, or the terrible affliction some people have when they're obsessed with corpses, often in a sexual way. "Carcase" is just a fun British way of saying carcass. To make matters clear, Invisible Man is definitely not about sex with dead carcasses. Nor is the Eliot play. In the play, Harry argues that the people looking at him aren't really seeing him, and he gets so angry about this that he compares their vision of his identity to necrophilia – what they see when they look at him, what they're so obsessed with, isn't a real human being at all, but a carcass. As such, the people looking at him are necrophiliacs. The narrator of Invisible Man faces a problem similar to Harry's. No one sees him properly. Does this mean Mr. Norton, Dr. Bledsoe, Brother Jack, Ras the Exhorter, etc. are basically trying to feed off the narrator's carcass? We'll leave the answer up to you.