on halo 3 how do you .........?

[Lolz]

How do you destroy the scarap i keep getting squashed by its feet

 

[Jack]

Shoot it in the leg with a gun (rocket launcher preferably) until it falls to the ground. Then you can get on it by jumping in the back. Work your way to the top area (you'll probably have to fight some enemies) and look around until you find a little area with a shield thing. Shoot or hit it until it is destroyed and you'll hear the scarab start to blow up. Hurry up and get off so you don't get blown up. It may take a few tries. Good luck.