The German Amazon site has an interesting pre-order bonus listed for the upcoming fighting game Injustice: Gods Among Us. German fans will be getting a free DLC pack called "Blackest Night" which will feature new skins for the characters based on their appearance in the famous Green Lantern story. The downloadable content will also feature a zombie mode in which all the characters turn into the undead.
While this free DLC appears to be targeted exclusively for German gamers, as has become standard practice this pack will likely be made available through the marketplace for whatever console you play your version on. Injustice: Gods Among Us is slated for an April 16th release date.
Source: Amazon Germany