AMU was a semi-popular Pokémon Trading Card Gamedeck archetype in late 2008. AMU stands for Azelf, Mesprit, and Uxie: the three key Pokémon in this deck. The deck's strategy centered around getting Mesprit LV.X, Uxie LV.X, and Azelf LV.X in play as fast as possible and consistently doing 200 damage with Mesprit LV.X's Supreme Blast attack. The deck faced severe consistency problems and, although it saw a small competitive play revival with the release of Level Max in the Platinum expansion, AMU was a short-lived and fairly unpopular archetype.
The strategy of this deck is to repeatedly use Mesprit LV.X's Supreme Blast attack, which does 200 damage provided there are both an Uxie LV.X and an Azelf LV.X in play. When using this deck, a player uses Trainer Cards such as Roseanne's Research to search for all of the Pokémon necessary and their non-LV.X forms. The most common way to make this deck is to have 3-1 lines (3 Mesprit, 1 Mesprit LV.X) for each of the three critical cards. However, 3-1 lines mean that the deck completely relies on none of the LV.X cards being in the prize cards, so some people take the more expensive route of 2-2 lines. The deck also often includes many Trainer cards to search for Basic Pokemon and something to knock out a Mewtwo (Mewtwo LV.X can block all damage from Psychic-type Pokémon). Once the player has all of the LV.X cards in play and any Mewtwo the opponent has are knocked out, they will repeatedly use Mesprit's Supreme Blast attack until they have taken their last Prize Card.
Mesprit - This card is necessary to eventually become Mesprit LV.X.
Mesprit LV.X - This card is used to repeatedly use the Supreme Blast attack. With every attack, It deals 200 damage, enough to kill almost any Pokémon in one shot.
Uxie - This card is necessary to eventually become Uxie LV.X.
Uxie LV.X - This card must be in play for Mesprit LV.X to use its Supreme Blast attack.
Azelf - This card is necessary to eventually become Azelf LV.X
Azelf LV.X - This card must be in play for Mesprit LV.X to use its Supreme Blast attack.
Roseanne's Research - This Supporter lets players search their deck for two in any combination of Basic Pokémon and Basic Energy cards and put them into the player's hand. Since every vital Pokémon in this deck is a basic Pokémon, this card is very useful for getting all necessary Pokémon to use the Supreme Blast attack.
Snowpoint Temple - This Stadium Card gives +20HP to all Basic Pokémon in play. This can give players an advantage if their opponent is using a deck with mostly evolved Pokémon.
Premier Ball - This Trainer Card allows the player to search their deck or discard pile for a Pokémon LV.X. This can be essential for the deck if one of their LV.X Cards is somehow discarded or is knocked out. It can also be used to find one of the LV.X Cards to set up for the Supreme Blast attack.
Night Maintenance - This card allows the player to search their discard pile for up to 3 in any combination of Pokémon and basic Energy cards. This can be useful if one of the LV.X Cards is knocked out. It can also be used to retrieve energy since the Supreme Blast has the player discard all Energy cards attached to Mesprit.
Energy Pickup - This card allows the player to flip a coin. If heads, the player searches their discard pile for a basic Energy card and attaches it to one of their Pokémon. This can be used to attach two Energy to Mesprit in only one turn as long as the player gets heads on the coin flip.