the Undead Nightmare Pack.

Unleashed upon the world of Red Dead Redemption, the Undead Nightmare Pack will feature an entirely new single-player campaign that follows John Marston as he tries to find a cure for the highly infectious zombie plague that has spread across the frontier. 

In addition to the lengthy single-player adventure, The Undead Nightmare Pack features brand new gameplay mechanics, weapons, zombie animals, mythical creatures and even a brand new secret location. 

All this, plus some new multiplayer modes and much more to be revealed in the weeks ahead.  The Undead Nightmare Pack will be available simultaneously for download via PlayStation Network ($9.99) and Xbox LIVE (800 Microsoft Points).  We'll have lots more info soon.

Additionally, we are going to be bringing you some free downloadable goodies in the next few weeks including the anticipated Hunting and Trading Outfits Pack which will give everyone the Savvy Merchant and Expert Hunter Outfits and related Challenges, plus special compatibility to enable everyone online to see the Red Dead Revolver multiplayer character skins being used by those who have purchased any of the DLC – we will have full details on this very soon.

--- what i find interesting is what kind of "mythical creatures" they will add