AKA: Revenge of the Crab Droid.
Here are more videos of mecha building instructions for your viewing enjoyment.
Star Wars Crab Droid. A quick, simple build. Video quality isn't that great though.
Mech + Instructions #3. Another build from Captain Hobby.
Custom Lego Crab Droid. This one has music. A more complex creation than the first crab droid video.
Lego Mech Armor. Kinda simplistic.
Lego Crab Droid Tutorial. More simplistic than the first Crab Droid video.