Stronghold the Moving Fortress (DPYG-EN030) [Duelist Pack: Yugi]

After activation, Special Summon this card in Defense Position; it is treated as an Effect Monster Card (Machine-Type/EARTH/Level 4/ ATK 0/DEF 2000). While you control "Green Gadget", "Red Gadget", and "Yellow Gadget", this card's ATK becomes 3000. (This card is still treated as a Trap Card.)