How do you bring down the spider droid in star wars the clone wars republic heros

If you mean the really huge droid in the first level, well first of all it is not a spider droid. It is called an octuptarra droid. Second, in order to bring it down, it's very easy once you get the hang of it. First of all, use the Force to bring down it's leg. In order to do so on the Wii, hit the Z button repeatedly. Then once the leg is stuck, jump onto it. Then jump towards the droid's eye/cannon. Use your lightsaber and slide the remote side-to-side in order to destroy the cannon. Repeat for the second leg. For the third leg, after bringing down the leg and jumping onto it, jump towards the droid's head. Once atop, stab your lightsaber into the droid's head and then it is nothing but scrap metal.