Kneel To the Frozen Sky: Brionac Dragon of the Ice Barrier

We have a level 6 WATER Sea Serpent with 2300 ATK and 1400 DEF. These stats make Brionac below average. Even Gaia Knight and Iron Chain Dragon can school him in battle and the attribute and type do not help very much at all.
The effect is what is so astounding. You can send cards from your hand to the graveyard in order to put cards on the field back to the owner's hand. This is primarily used in zombie decks in order to clear the way with massive Mezuki, Burial and Plague plays for the one turn kill, but it also ends up working for almost every deck as it is a generic Synchro. Most decks can easily make a level 6 Synchro, so it is basically an answer to cards that would otherwise cause you trouble, like Stardust, Colossal and Armor Master and in tough spots, Dark Armed Dragon.

You can also use his ability to put himself back to the extra deck, so that your opponent can't play there Mind Control and Brain Control. His effect is rather costly, so unless you REALLY need to get a card off the field or you are going for game, Goyo Guardian is a better choice or even Gaia Knight.