Excuse me, later days I tested my Gladiator Beasts. And then I summon Elemental HERO Prisma and I have a gladiator beast monster. My plan is to fusion summon gladiator beast gyzarus with prisma effect to send bestiari from deck to the grave. But I clicked the Prisma and he don't show a "activate" button to activates prisma's effect. Then I just play with other decks cause just prisma. Why my prisma can't activate? Thanks before.