Basically, the square teleports to a location beneath the bedrock when I deselect it. The location is 0, -1, 0. The derpy box is visible from anywhere in loaded chunks. It remains even if I remove the ring and even if I reload the game. EDIT: It only exsts while the ring of Loki/Aesir is in my inventory, but it does not need to be equipped.

This was already mentioned and closed in #899
Edit: the ring in inventory but not equiped part could be a bug