When Dede smashes the ground these little stars appear. Swallow one of those and shoot it back on him. It took me a while before I figured out that part too. I never knew how to actually hurt the guy.
Did you already buy Star Fox 64 3D and Kirby: Mass Attack or are planning to? and are you anticipating Kirby's Return to Dreamland or Kirby's Adventure Wii if you live in Europe?