Elemental Hero Thunder Giant [DP1-EN011] Rare

"Elemental Hero Sparkman" + "Elemental Hero Clayman" This monster cannot be Special Summoned except by Fusion Summon. Discard 1 card from your hand to select and destroy 1 face-up monster on the field with an original ATK that is less than the ATK of this card. You can only use this effect once per turn, during your Main Phase.