Gem-Knight Dispersion - Battles of Legend: Monster Mayhem (BLMM)

Activate 1 of these effects (but you can only use each effect of "Gem-Knight Dispersion" once per turn);
• Fusion Summon 1 "Gem-Knight" Fusion Monster from your Extra Deck, using monsters from your hand or field. Up to 2 monsters from your Deck/Extra Deck can be used, if they are non-Rock "Gem-Knight" monsters and you have "Gem-Knight Fusion" in your GY.
• Add 1 "Gem-" monster from your Deck or banishment to your hand, also any effect damage your opponent takes during the Main Phase this turn is halved.