During your Main Phase, if your opponent controls a monster: You can Fusion Summon 1 non-Rock "Gem-Knight" Fusion Monster from your Extra Deck, using monsters from your Deck as material, also you cannot Special Summon monsters from the Extra Deck for the rest of this turn, except "Gem-Knight" monsters. You can only use this effect of "Scatter Fusion" once per turn. When this card leaves the field, destroy all monsters Summoned by this card's effect.