Enter a Scarab glitch

Performing the Glitch
Method #1. Get inside the Scarab in The Great Journey is a glitch in which you can get on board the Scarab before the cutscene "Backseat Driver" in Halo 2. Although you can get inside it, you cannot operate it in anyway at all. When you get to the platform, grenade jump to one of the legs. Then crouch jump onto the deck. You can now go inside the Scarab (there is no shield), and push the invincible Johnson to the edge of the Scarab, and get him to fall off the Scarab's deck, and down to the sand far below.

Method #2. When Johnson jumps aboard it for the first time, before that, you must bunny hop to the edge of the platform. When you get there, jump. It is extremely important that you time this perfectly. As the Scarab moves back a bit, jump right then. You should end up going higher than usual. This can take a few attempts. If it works, you will jump towards either the left or right leg. If done correctly, you will land on the leg. Then crouch jump onto the deck.

Method #3. Take a Ghost throughout the entire level and bring it with you to the platform with the Scarab. Boost at the Scarab, and stop right before the edge. Jump on top of the Ghost and then up to the deck of the Scarab.

Note: Pushing Johnson over the edge will stop the cutscene. Do not attempt this unless you want to revert to the previous checkpoint, or have already beat the game.

Method #4. There is another way to do it. First you need to activate the Sputnik skull, then go to the level The Great Journey, go to the part where two Wraiths come to keep you out of the structure. To your right is the rock that hid the closer Wraith from view.