If 2 or more cards are in the same column, you can Special Summon this card (from your hand) in that column. You can only Special Summon "Mekk-Knight Green Horizon" once per turn this way. When an attack is declared involving this card and an opponent's monster in this card's column: You can target 1 "Mekk-Knight" monster in your GY; add it to your hand.