Work continues at a frantic pace on single and multiplayer. Sometimes to two collide! Lars, the multiplayer designer was playing through on of the single player missions when suddenly he was surrounded by butterflies. 'I thought I was going insane," said Lars. But he asked a programmer - and discovered that some wit had replaced the normal garbage collection routine (the deletion of unused objects like dead bodies and dropped, spent weapons) with a more elaborate one. The corpses of fallen Covenant currently turn into a "flock" of monarch butterflies, with flapping wings. Bizarre. And I'm assured this took about a minute to implement (this statement to head off the inevitable flames from backseat developers).