In Metropolis, kill a Jackal on the Scarab. If it is on the right place, it will appear blue, as though it were inside the Scarab's tech innards. This is the result of a lighting glitch; a part of the Jackal's corpse is "inside" the Scarab, so the game assumes that the entire Jackal is in the Scarab's interior, and lights it accordingly. Meleeing the body will cause it to change to other colors, strangely including yellow and red. Shining your flashlight on the affected corpses will temporarily revert them to normal.