How do you beat the crab on Halo 3?

Answer 1

Once you get it down by destroying its legs go inside. There is a panel with a shield over it. Knock out the shield and shoot the thing until it blinks red. Then run!! If it blows up and you're still on it, you're dead. Turbo-117

Answer 2

If you mean the Scarab (big, four legs, lots of guns)...

Use rockets and shoot the insides of its legs on the knees until it sets off an alarm and lowers itself down.

When it lowers down, go behind it and jump in through the entrance (watch out for the turret that is on the back). Once you're in go up the ramp and go around the walkways (more gunners, watch out).

When you find another room with something that looks like a big blue eye inside, go in and smash the 'eye' repeatedly, it'll break, then smash the armoured plate on the inside. A red light will start flashing in the middle of it.

You should run and get away as fast as you can because when it blows up, it can blow you up too.

Hope that helped :)

Answer 3

First you have to takedown its leg so its stopped moving then get on board find the heart and destroy it.