The card is called Beyond Fusion.

Fusion Summon 1 Fusion Monster from your Extra Deck, using monsters from your hand or your side of the field as Fusion Materials. If your opponent controls a monster(s) , you can also use monsters in your Deck as Fusion Material. You can only activate 1 "Beyond Fusion" per turn.

I know it might be considered "broken" lol but I really want to test this in something like heros or even something fun like fluffals.