Monsters vs Aliens

You can get this the first time you start playing with B.O.B. The first segment of chapter 1 will be using Ginormica. The second will be using The Missing Link. The third will be using B.O.B. As soon as you start, there should be a box nearby (which, if you have the tutorials on, will tell you to destroy them with the X button). Don't destroy them. Instead, press B to swallow the item, then press B again to spit it out. Keep repeating this until the Glutton achievement: When the Glutton achievement pops, continuing using the swallow-then-spit technique to get this achievement.