Max Metalmorph 424

Card text

Tribute 1 face-up monster; Special Summon 1 monster that cannot be Normal Summoned/Set and mentions "Max Metalmorph" from your hand, Deck, or GY, then you can equip this card to it with the following effect. ● The equipped monster gains 400 ATK/DEF, it cannot be destroyed by Spell or monster effects, also your opponent cannot target it with monster effects or Spell Cards or effects. You can only activate 1 "Max Metalmorph" per turn.

Image source: CardTrader