Doesn't make the decision any easier, I'm afraid. Sure the Unknowing is a strong contender, but I feel that was more madness, skin and the world attempting to tear itself apart at its seams than weird.

I will disregard any living beings that might be valid answers, but give you a small selection rather than making an inventory list of all of which we have in Artefact Storage: A star made of darkness, a door that is neither a door nor truly there and a coffin that leads towards a place far below existence itself, a place where there is no up and the weight of reality pushes down on you.