This monster can only be Special Summoned by removing from play the above monsters on your side of the field. You do not use ''Polymerization'' to Special Summon this monster from your Fusion Deck. Discard 1 card from your hand to destroy 1 face-down Mons

"Y-Dragon Head" + "Z-Metal Tank"

This card cannot be Special Summoned except by removing from play the above monsters on your side of the field; then you can Special Summon this card from your Extra Deck (You do not use "Polymerization"). Discard 1 card from your hand to destroy 1 face-down Monster Card on your opponent's side of the field.