Guess I had too much Christmas "cheer" yesterday, so I'm a bit slow on the uptake tonight. What reference?
Good one. I had to look it up. My favorite Zep.
http://www.youtube.com/watch?v=YWOuzYvksRw
The cover and inside sleeve of this album, created by Hipgnosis, features various images of people interacting with a black obelisk-shaped object. Inside the album sleeve, the item is referred to simply as “The Object.” It was intended to represent the “force and presence” of Led Zeppelin.[2] In the liner notes of the first Led Zeppelin boxed set