Target 1 face-up monster on the field; equip this card to that target. It gains 300 ATK/DEF. If it attacks, it gains ATK equal to half the ATK of the attack target, during damage calculation only.
Rulings
Individual Card FAQs
If you equip two copies of "Metalmorph" to a single monster, its ATK and DEF will be increase by 600 and the second effect will add half of your attack target's ATK to the equipped monster's ATK twice.
The second effect of this card only increases the equipped monster's ATK when it is the attacking monster (during your Battle Phase) not when it is being attacked during your opponent's Battle Phase.
If "Reverse Trap" is activated, a monster equipped with "Metalmorph" will have its ATK and DEF decreased by 300 points, but the second effect of "Metalmorph" will be unaffected and still increase the equipped monster's ATK by an amount equal to half of the attacked monster's ATK.
Netrep Rulings
“Metalmorph” may be activated in the Damage Step.
Multiple “Metalmorphs” equipped to the same monster will have a cumulative effect.
Trap|
Normal