Activate only during your opponent's Main Phase. After activation, Special Summon this card; it is treated as an Effect Monster Card (Machine-Type/EARTH/Level 4/ATK ?/DEF ?). (This card is still treated as a Trap Card.) If this card is selected as an attack target, the ATK and DEF of this card become the ATK and DEF of the attacking monster. This card is Set in its Spell & Trap Card Zone during your opponent's End Phase.