The Petrification Weapon, also known as the Medusa, is a technological device that can cause petrification which was used as a weapon by Kirisame and Ibara.

At an unknown point in time, the device came to be on Treasure Island and abused as a punishment-dealing tool.


The Petrification Weapon is first seen being thrown by Kirisame attached to a piece of rope, its effect activating after a certain distance. The rope presumably provides ease of recovery, while the throwing action allows the petrification effect not to consume the thrower.

When thrown into the air it creates a limited-scale petrification event that turns everyone within its radius into petrified statues. These statues can be revived using the revival solution that Senku made.

The radius and activation time of the weapon can be altered by verbal commands, as demonstrated by Ibara to silence Kirisame after the latter learned of his betrayal and later upon turning Yo to stone to retrieve the device from him.

At present, the largest known radius of the device seems to be the entire diameter of the Earth, around 12,800 kilometers, although if the weapon is actually capable of achieving such a range in unknown.[1]

It appears to take the form of a Trefoil Knot and appears electronic in nature. It is currently unknown to where it originates. It is told from Matsukaze that multiple copies of the device fell from space onto Treasure island.



Prior to the present, several of the Petrification Weapons fell from the sky. A majority were collected by brigades who were destroyed by a warrior that soon lost his life but his servant Matsukaze carried on his work. Wanting to warn future generations, Matsukaze petrified himself.[2][3] However, the lone weapon would go on to be passed down through leaders of the island until falling into the hands of Ibara who usurped the leader.

Amaryllis and her four friends being petrified

Petrification Weapon being used.

In the year 5736, the Petrification Weapon was used by Kirisame and Mozu against Amaryllis and her four friends to prevent them from fleeing the Island.[4]

Treasure Island Arc

During the year, 5741, Kirisame would continue to use this weapon and petrified the crew of the Perseus.

She later does so against Kohaku and Ginro (unintentionally saving from his grievous wound) on orders of Ibara.

Having heard of this weapon, the remaining members of the Kingdom of Science allied with Mozu for the device.

When the truth of the Head of the Island is revealed, Ibara has the entire island petrified to cover his tracks. However, Senku survived the event and after grueling tug of war with Ibara for the device, he petrified Ibara.

With Ibara defeated, the Kingdom of Science obtained the weapon.

Whyman attempts and fails to set the device off at a radius of 12,800,000 meters or 12,800 kilometres. Senku points out this covers the entirety of Earth.[1]

New America City Arc

Once depetrified, Matsukaze revealed there were other devices that fell.[2]

Senku later reveals the weapon is almost depleted of power and uses the device's remaining power to petrify Tsukasa Shishio, saving his life.[5]


  • The unofficial name for the device, the Medusa, is a reference to the Gorgon from Greek Mythology.
  • The device has a finite amount of power, another nod to the formula E=Mc squared. (Which Senku has noted a few times already on how energy cannot be created from nothing).
    • It is unknown if Senku will find another way to power it.
  • The user must be really close to the device to verbally activate it.
  • It was mentioned a voice was heard with the devices falling, it is unknown if it is connected to the mysterious creator.



  1. 1.0 1.1 Dr. Stone Manga: Chapter 138, Pages 16 - 17
  2. 2.0 2.1 Dr. Stone Manga: Chapter 139
  3. Dr. Stone Manga: Chapter 146
  4. Dr. Stone Manga: Chapter 106
  5. Dr. Stone Manga: Chapter 141

Community content is available under CC-BY-SA unless otherwise noted.