Forum:The Supernovas

I was thinking that this part of the Supernova chapter, that Jewelry Bonney and her crew were to be rescued. Here's how iIsee it. The marine ship, lead by Admiral Akainu, moves into a mysterious fog. While they weighed anchored, a marine goes into the prison cell. The Bonney pirates gave him a nasty look, but it wasn't a marine officer, it was a pirate captain in disguise. He convinces the captured pirates to listen to his plan. When he goes on top of the deck, without his uniform, he asks Akainu to fight him on the shore for the fate of the Bonney pirates. If the pirate wins, he will take the caught pirates with him and if he loses, the Bonney pirates are his as well as the pirate captain's crew. Both of them agreed and the stranger jumped on the ship into the fog.

Moments later, Akainu and his crew came onto an island with the Bonney pirate on the deck of the Marine ship and Jewelry Bonney chained to two large piecof lumber shaped as an "X". The mysterious pirate captain walks toward the Marines and after a few more steps toward the fight, he stopped. When Akainu used his lava attack, the captain put up his right fist and stood still. After the dust cleared up, they found out that the captain turned himself into stone. They found out that he ate a devil fruit that caused him to be unaffected. After he scrapped off the lava in his rock body, he performed his own attack. He jumped into the air and when he punched the ground and caused a tremor. The tremor caused the marine officers to loose their balance, but not for Akainu. When he was waiting after the tremor was finished, the captain charged in as a boulder at high speed and attacked the Admiral in the chest. During the battle, the captain's crew quietly released the Bonney pirates. Akainu ad the captain kept dodging each others attacks until he shot Akainu in his left arm with his pistol that had a silencer at the tip. The admiral attempted to use his lava power against the pirates who are escaping, but he can't. The bullet in his body was made out of prism stones. The marines were about to attack but Akainu refuses them to interfear with his fight. The captain jumped again but higher than his previous jump and caused a more powerful tremor. Powerful enought to create a crack on the ground and caused the marines and the weakened admiral to fall, as well as the timber holding Bonney to fall onto the marine ship.

When the marines were getting up, they discovered that the captain was gone. They turned around and found him with Bonney in his arms. When they tried to shoot him, he jumped of the ship. They didn't hear a splash so they checked it out and they found out that the pirate captains on a small ship with what appears to be an small engine. The stone captain waved to them and saided to a large ship with his and Bonney's crew on it. Once they went aboard, they set sail. Akainu saw the whole thing and shouted in anger with the marines shaking in fear. While the pirates were sailing, the stone captainoffered to help Bonney and her crew go to the new world.

What type of stone is this? Doesn't magma just melt the stone/rock into more magma?