"Elemental Hero Neos" + "Neo-Spacian Flare Scarab"
This card can only be Special Summoned from your Fusion Deck by returning the above cards from your side of the field to the Deck. (You do not use" Polymerization".) This card gains 400 ATK for each Spell and Trap Card on the field. This card returns to the Fusion Deck during the End Phase.