Borderlands recently got an update which added Steam achievements and new hardware support. That update also may have laid out, in extreme, spoiler-filled detail, the next downloadable expansion for Borderlands.
The new Borderlands patch featured a folder with details about the future of the game. The next expansion appears to be heavy on Claptraps – the small, funny robots in-game. It turns out that you may be fighting them and cybernetic zombies in the game’s next add-on.
Gearbox forum members found details about the next DLC in the patch files, such as: "Interplanetary Ninja Assassin Claptrap" that leads a robot revolution against the Vault hunters. Your task in the next DLC pack is to take down those Claptraps and the re-animated human-Claptrap hybrids. Skag claptraps, Rakk claptraps, Psycho Midget claptraps and dozens of variations on the Claptrap, only way more evil, will be your enemies in the expansion, according to those update files. The DLC appears to span some 21 missions—"9 Main Missions, 12 Side Missions"—and will see plenty of familiar faces return.
If you want to know more spoilers simply visit Gearbox forums and read it. Gearbox didn’t officially confirm the DLC yet.