Dragon Egg

The Enderdragon Egg is an item first mentioned by Notch on the 27th of October, 2011 on which Notch is supposedly working before the release. Sharing it's name with the Enderdragon, the item and the mob may be related to eachother. However very little information has been made available on the purpose of the egg thus far.

Trivia

 * Enderdragons drop a single obsidian block as of 1.9 pre-release 5. Since obsidian blocks are already present in abundance in The End and serve no direct purpose in The End as of yet, it is unknown whether the obsidian block is a placeholder or not. Even so, it is unknown whether the Enderdragon will remain to drop the obsidian block, or at some point the egg or another item in the near future.
 * It is not known what purpose the egg will have, or if the egg will be an item or another kind of block or entity.

"There isn't a lot of interesting minecraft news these days because of the feature freeze, so I will just say one thing: egg."
 * Notch's tweet's

"I was talking about ender dragon eggs."