Although Johnny uses Metalmorph, it is the same card as the Magic Metal Force that Bandit Keith used in Duelist Kingdom. The proper name for the card is Metalmorph.
The Heavy Metal King’s defense is originally shown as 1700, but then increases to 1800 for no apparent reason.
Johnny made it sound like the Heavy Metal King was a different monster, when technically it is just the Musician King powered up with the effect of Metalmorph.
When Johnny flips Metalmorph, the Musician King’s card shows that its ATK is 1800. His actual ATK is 1750.
Actually Heavy Metal King’s DEF should’ve been 1800 the increase from 1500 to 1700 was the mistake because Metalmorph increases both ATK and DEF by 300 points.
Water Omonics was a naked monster but they covered her with scales, same thing with the actual cards.
This duel never happened in the manga.