Luo Fan specifically ordered the Cat Corps to keep an eye out for the Baku Baku no Mi, not because he was interested in its ability to swallow everything, but because he was after a metal created using its power—wapol metal.
Regarding this metal, the story begins after Wapol was driven out of the Drum Kingdom by Luffy and his crew.
(P.S. This story was serialized in the manga's cover stories; some readers might not know it, so here is a brief explanation.)
After being sent flying by Luffy, Wapol went to other islands and, as before, ate whatever he saw.
Due to the Baku Baku no Mi's ability, Wapol would manifest characteristics of whatever he ate; he successively became a Candle Man, a Chair Man, a Zhou Shuren (Tree Man), and so on.
He ate his way from the woods all the way to a city, but because he ate too much and caused massive destruction to the city, he attracted the pursuit of the Marine.
This time, Wapol didn't dare to eat recklessly anymore. To evade the Marine, he lived a destitute life as a vagrant in a junkyard.
With no income and having lost his food source, Wapol could only start eating the trash in the junkyard.
Among the trash were scrap metal and broken toys. Under the power of the Baku Baku no Mi, these scrap metals and broken toys actually fused to become rather magical toys.
Wapol made a fortune by selling these toys to children, and his business grew larger and larger.
After a scientist discovered that Wapol's toys contained a special metallic component, Wapol's fame skyrocketed. He not only caught the attention of the World Government but also leaped into the ranks of the super-wealthy.
In the end, he even gained recognition from the World Government, established the Black Drum Kingdom, became its king, married Miss Universe, and returned to the peak of his life.
The fundamental reason why Wapol could stage such a comeback and be so highly valued by the World Government—to the point where they used noble status and a new kingdom to win him over—was because of wapol metal.
In the original work, there are two most famous items directly or indirectly stated to be made of wapol metal:
The first is General Franky, built by Franky.
When General Franky first debuted, Franky said that he had incorporated the shape-memory alloy, wapol metal, during its construction.
The second is the Raid Suits of the Vinsmoke Family.
(P.S. Perospero referred to the Raid Suits worn by the Vinsmoke Family as 'Shape-Memory Armor'.
When Franky explained that General Franky incorporated the shape-memory alloy wapol metal, the term he used was identical to the one Perospero used for the Germa Raid Suits in the Japanese raw scans.
So, this is a hint that the Germa Raid Suits also use wapol metal.)
Regarding the characteristics of the shape-memory alloy, the Vinsmoke Family's Raid Suits actually demonstrate them very well; a small canister can hold an entire suit, which is an embodiment of wapol metal's memory and deformation capabilities.
Similarly, General Franky's battles also showcase this ability.
Of course, if it were just memory and deformation, Luo Fan felt that Wapol wouldn't be worth such a high price for the World Government to win him over.
What's more important should be wapol metal's self-recovery capability. This was reflected in General Franky's battle on Punk Hazard, where Baby 5's scythe once pierced through General Franky's arm.
At that time, Franky calmly pulled the scythe out of the arm and immediately blasted Baby 5 away with the General Cannon.
To put it bluntly, the General Cannon is just a larger version of the Coup de Vent, and it also requires charging. During General Franky's charging process, there was no sign of damage on his arm, which perfectly demonstrates wapol metal's self-recovery property.
Franky once said that with the help of wapol metal, he could fulfill Vegapunk's old dream.
Anything related to Vegapunk is more likely than not connected to the lineage factor, and the lineage factor is closely related to Devil Fruit abilities. This also indirectly illustrates the value of this fruit.
Thinking of this, Luo Fan no longer hesitated and directly gave an order to Big Cat, telling the Cat Corps to confirm which auction house the Baku Baku no Mi would be auctioned at.
A moment later, Big Cat sent back word: the Baku Baku no Mi would be auctioned tomorrow night at the Island No. 4 auction house.
Hearing this, Luo Fan sighed inwardly: 'Why is it the Island No. 4 auction house again? What a coincidence!'
The next evening, Luo Fan, Big Cat, and Cat Two arrived at Island No. 4. Noy's fear of the Celestial Dragons still lingered; Luo Fan was afraid she would be nervous, so he didn't let her come along.
The three Cats lay on a large tree opposite the auction house, watching the guests enter one by one.
Among the guests entering the auction, Luo Fan unexpectedly saw that female Celestial Dragon and the Orange Cat she was holding in her arms.
The Orange Cat also saw Luo Fan and immediately became restless.
Luo Fan released his Conqueror's Haki toward the Orange Cat. The Orange Cat trembled in fear and didn't dare to make any further movement.
Just as Luo Fan was about to continue teaching the Orange Cat a lesson, a middle-aged man dressed in fine clothes walked over and tried to strike Up a conversation with the female Celestial Dragon.
From his words, Luo Fan learned that he was actually the current King of the Drum Kingdom, Wapol's father.
It was truly a case of'searching far and wide only to find it easily.' Originally, Luo Fan was wondering how best to sneak into the auction site, but now everything was simplified.
Since Wapol would eat the Baku Baku no Mi in the future, his father would most likely buy it this time. Luo Fan just had to wait for the auction to end and then steal it from Wapol's father.
And indeed, Wapol's father successfully won the bid for the Baku Baku no Mi.
After leaving the auction house, Wapol's father was accompanied by a squad of guards.
These guards could at most intimidate ordinary people and posed no threat to Luo Fan, but out of caution, Luo Fan still didn't act personally.
Because no matter what, Wapol's father was the king of a country. A king being robbed on the Sabaody Archipelago would certainly cause quite a bit of trouble and might even attract a Marine Admiral. So, it was better to have the Cat Corps take action at this time.
Under Luo Fan's command, Big Cat and Cat Two gathered a group of Cats and suddenly burst out of the forest, pretending to be in a massive cat fight.
The scene of hundreds of Cats fighting was simply too chaotic. Luo Fan took the opportunity to slip into the crowd of Cats and released his Conqueror's Haki toward Wapol's father and his guard squad.
These people were instantly knocked out. With a swipe of his claws, Luo Fan took the Baku Baku no Mi from the arms of Wapol's father into his Storage Space, then ordered the Cats to attack Wapol's father and his guards.
Hundreds of Cats swarmed them. By the time the Marine arrived, they only saw the King of the Drum Kingdom and his guards with their clothes torn to shreds and their bodies covered in cat scratches.