Within the game's files is a gun with the model ID "WP_A_9999" that when loaded is revealed to bear an identical resemblance to the Lancer from Gears of War, originally released as an Xbox 360 exclusive. It's unknown why this weapon wasn't removed from the game considering how out of place it is with the rest of Demon's Souls, but the most likely theory is that it was leftover test data originally stemming from when From Software developed the Xbox 360 exclusive Chromehounds.