Particle Fusion
Send, from your side of the field to the Graveyard, the Fusion Material Monsters that are listed on a "Gem-Knight" Fusion Monster Card, then Special Summon that Fusion Monster from your Extra Deck. (This Special Summon is treated as a Fusion Summon.) When you do: Banish this card from the Graveyard to target 1 "Gem-Knight" Fusion Material Monster used for the Fusion Summon; the Fusion Summoned monster gains that monster's ATK until the End Phase.