Gutsu Gutsu no Mi

The Gutsu Gutsu no Mi is a non-canon Paramecia-type Devil Fruit that allows the user to turn their body into a blast furnace and melt metals inside it, making them a Blast Furnace Human (溶鉱炉人間). It was eaten by Bill.

Etymology

 * "Gutsu Gutsu" is the Japanese onomatopoeia for something boiling.

Strengths and Weaknesses
The main strength of this fruit is the ability to solidify the molten ore in the user's body and shape it into anything the user desires, including metal weapons. The user is also able to launch the extremely hot molten ore out of their body to attack others. They can also turn people into solid silver statues. They are also granted immunity from being burned by the molten ore and the initially hot metal it is formed into.

It seems that the user requires a supply of ore inside them in order to be able to form weapons, forcing them to constantly consume ore in order to use the fruit, although the more ore is consumed, the more powerful is the user, to the point Bill bloated to huge proportions after eating too much ore.

Usage
By eating ore, Bill can send it into a blast furnace inside his body, which will make his body glow orange and exude steam. He brings out the ore to use for whatever fits the situation, such as weapons for when he is attacking. He also sometimes attacks with molten ore. Additionally, he uses his fruit to also increase the military strength of his entire crew, giving all of them weapons.

Trivia

 * The basis of his power has many similarities to Enel's Gloam Paddling, as both use heat to melt metals freely into new shapes.
 * This is the third filler devil fruit that grants the user control over heat coming from their body.
 * This power is also similar to the Ami Ami no Mi and the Baku Baku no Mi as both also requires the consumption of inedible things to fully use their capabilities, although this one only works with metallic ores.