Semi-fake area glitch

In Halo 3 on The Storm, proceed normally until you are at the part where you must kill the Anti-Aircraft Battery. Defeat all the [enemies and allies (do this on Co-op so the Arbiter can't kill you). Walk away from the gun and towards the large canyon. Go to the part of the ledge closest to the other side, and grenade jump. If done correctly, you will survive to make it to the other side. However, the second player who was left behind will be unable to do it for some reason. Have them jump into the chasm and die (laugh at the horrible death noises). They will respawn on the other side.

On the glitch side, walk around at your leisure. Some things are nonexistent as physical objects - you can walk through certain fences, and a large boiler. Invisible wall appear in certain areas. The nonexistent object are that way because they were programmed to just be seen, not to be interacted with.

DO NOT THROW GRENADES WHILE EXPLORING THIS AREA!!!

Any grenades thrown will (for some reason) create a very short height barrier that sometime causes death if touched. When you are done exploring, have one player commit suicide to gain grenades, and grenade jump back to the real side. Have player 2 commit suicide. You may then continue normally.