D/D/D Wave Oblivion King Caesar Ragnarok [MP16-EN138] Super Rare

2 "D/D/D" monsters
Once per turn, when an attack is declared involving this card: You can target 1 other "D/D" or "Dark Contract" card you control; return it to the hand, and if you do, equip 1 face-up monster your opponent controls to this card, except the battling monster. This card gains ATK equal to the combined original ATK of the monsters equipped to it by this effect.