Since this is the first combo to be added in the combo section, I thought I would use my favorite combo. Here goes...
In the Duel Monsters game, there are very few ways to actually search your deck for Magic and Trap cards. However, when this combo works, you can get up to 2 Magic and Trap cards from your deck in your hand.
Those of you who are familiar with the above cards have probably already realized the combo. Activate Magical Silk Hats during your opponent's Battle Phase, choose any two non-monster cards from your deck that you would rather have in your hand, and place them out as fake monsters. With a bit of luck, your opponent will attack the Penguin Soldier, and when the Penguin Soldier flips, it's effect can send your two non-monster cards up to your hand, where you can use them.
However, sometimes the fake monsters will be attacked. Odds are in favor of you're being able to send one card non-monster card up to your hand. Still, even if both of the cards are attacked, you can still extend this combo. Now that they're in your Graveyard, retrieving them is easy with Saint Magician(RB-36) and Dark Mask(RB-14).
However, to guarantee that your Penguin Soldier will be attacked, you can attach a Ring of Magnetism to it! According to the rulings on the official Konami of Japan website, equip Magics will still work even if the monster they are attached to is flipped over by Magical Hats! In this case, you are required to reveal to your opponent the location of Penguin Soldier if they still choose to attack.
Of course, that is the ultimate way to kill the Penguin Soldier combo...to not attack. ^_^
