From Bulbapedia, the community-driven Pokémon encyclopedia.
Stallgon is the name of the deck used by David Cohen, the Senior Division Finalist in the 2009 World Championships. The deck is a specific build of the Mother Flygon archetype that includes the use of Mewtwo LV.X's Poké-Body, Psybarrier. The main attackers of the deck are Rising Rivals Flygon, Secret Wonders Flygon, and Flygon LV.X, utilizing all attacks depending on the situation. Flygon also provides free retreat to the other Pokémon in the deck with the use of its Poké-Body, Rainbow Float, while Flygon LV.X's Poké-Body Wind Erosion discards from the opponent's deck.
Claydol's Cosmic Power Poké-Power and Uxie's Set Up Poké-Power provide draw support, Azelf's Time Walk retrieves necessary Pokémon from the Prize cards, Nidoqueen's Maternal Comfort heals 10 damage from all the player's Pokémon between turns, and Unown G acts as a Pokémon Tool to prevent Weakness damage.
Other included Pokémon LV.X include Mewtwo LV.X and Palkia LV.X. Mewtwo LV.X's Psybarrier Poké-Body prevents all effects of attacks, including damage, to Mewtwo LV.X from the opponent's non Evolved Pokémon. Palkia LV.X's Restructure Poké-Power forces both the player and the opponent to switch Pokémon, which the player can then Retreat for free utilizing Flygon's Rainbow Float.
Stallgon is one of the four 2009 World Championships Decks, released on October 28th, 2009. Each deck comes packaged with a 2009 World Championships Booklet. Each card features a silver border, Cohen's signature, and limited edition 2009 World Championships back. None of the cards are tournament legal.
Flygon and Flygon LV.X are a formidable combination, as David Cohen proved with his Stallgon deck. Flygon's Sand Wall attack takes out your opponent's Stadium cards and Flygon LV.X can blast one of your opponent's Pokémon LV.X for 150 damage. Best of all, Flygon LV.X can use Wind Erosion to put your opponent at risk of losing...by running out of cards!