Pikmin Cheats :
FiReworks out of Onion's
This best works when your near an Onion but you can do it anywhere you like. What you do is you press the C button to dismiss your Pikmin, then you press the 2 button to...
1. Be Invinsible from enemy's
2. Lie down
3. Press the 2 button when near a group of Pikmin and they will carry Olimar to their Onion. It won't work, but after 1-2 seconds, fireworks come out of the Onion the Pikmin carried Olimar to.