Ruyi Jingu Bang, also known as Ruyi Bang or Jingu Bang, is the poetic name of a magical staff wielded by the immortal monkey Sun Wukong. The name is translated as "The Compliant Golden-Hooped Rod". The staff is initially described as a pillar of black iron twenty feet in height and the width of a barrel. The weapon is banded with a gold ring on each end, as well as the inscription along the body reading "The Compliant Golden-Hooped Rod. Weight: thirteen thousand five hundred catties.
The staff first appears in the third chapter when the Monkey King goes to the underwater kingdom of Ao Guang, the Dragon King of the East Sea, looking for a magic weapon to match his strength and skill. When all of the traditional magic weapons, be it swords, spears, and halberds weighing thousands of pounds each, fail to meet his standards, the dragon queen suggests to her husband that they give Sun a useless iron pillar taking up space in their treasury. She claims that the ancient shaft had started producing heavenly light days prior and suggests that the monkey is fated to own it.
Ruyi Jingu Bang is able to grow on command to what the owner says and is capable of injuring and even killing almost all gods. The staff is also deceptively but monstrously heavy, with few beings besides Sun Wukong being able to even lift the staff. Ruyi Jingu Bang's size can be altered according to the Monkey King's will. It can grow broader or slimmer and taller or shorter at will. It can reach incredible lengths, as it was able to reach all the way from the moon to the earth which is 384,403 km (238,900 miles) long.
On command the staff can become lighter or heavier. Either of which is the norm for Sun Wukong and is heavy by many people's standards, example being that just placing it onto the floor, it was able to create cracks in the ground that reverberated up a gigantic hole up to its surface. Making it lighter vastly increases movement speed. Ruyi Jingu can even make multiple copies of itself along with Wukong's own copy, however, the duplicate's staff is slightly weak. The staff is also incredibly durable, with few if any attacks able to break the staff and even when it is broken it can regenerate. So far only Zeus with his Master Bolt managed to cut it, something that the Jade Emperor himself failed to do.