Once it was explained to me that Jesus returned in his astral form and appeared to his disciples but it was misunderstood at some point as being a physical return. He then ascended to heaven in his astral body. Returning from the dead does sound like a Medieval obsession.
I know there are probably esoteric explanations that go with some contexts... but the undead Jesus meme tickles me because the undead types are all from Dungeons & Dragons! It’s maybe a bit of an in joke.