This iron cudgel counts as a +3 magic quarterstaff. Originally the magic needle that a dragon God used to direct the Ocean currents. Afterwards, it was used as the central support for his Treasure Hoard Chamber. The Ruyi Jingu Bang is furthermore indestructible and capable of extending or shrinking to unbelievable sizes, from a small as a needle to large enough to reach the heavens. It was created by a God of Martial Arts and Longevity as a gift to that dragon God. 

Change size. The Ruyi Jingu Bang is by default a weapon sized for medium creatures. As a bonus action, you can command the staff to become tiny, small, medium, large, or gargantuan. Halve the weapon damage dice if the staff becomes small, and quarter it if it becomes tiny. Double the weapon dice if the staff is Large, triple the weapon dice if it’s Huge, and quadruple the weapon dice if it’s Gargantuan. This size change remains in effect until this ability is used again, or the weapon is safely tucked away. To attack with this weapon, you must be of equivalent size, larger, or have a strength equal to or greater than 24.

Safely Tucked Away. When you stow this weapon, you can choose to shrink it to the size of a needle and hide it behind your ear. When you draw the weapon as part of an action, you can choose to revert it to the default medium size. In its needle form, it deals 1 piercing damage on a successful attack.

Indestructible. This artifact cannot be destroyed.

Into the Heavens.

As an action, the staff becomes a stationary pillar 9 feet in diameter stretching from the ground to the sky where clouds obstruct your view of the top. The clouds at the top also conceal the view to the ground and act as a portal to a good-aligned outer plane chosen by the DM.

Climbing the staff requires a successful Strength (Athletics) check. The DC for this check is 10 due to the magical nature of the staff providing handholds. On a successful check, a creature can climb at a rate of 300 feet per minute. Therefore, reaching the lower cloud layer (approximately 6,500 feet up) would take about 22 minutes, and reaching the higher cloud layer (approximately 20,000 feet up) would take about 67 minutes. These times can be halved with a successful DC 20 Strength (Athletics) check, representing a more rapid climb.

Climbing the staff for more than 10 minutes requires a DC 10 Constitution saving throw at the end of each subsequent 10-minute interval, with the DC increasing by 1 for each additional interval. On a failed save, the climber gains one level of exhaustion.

Upon reaching the portal at the top, climbers will find it guarded by a Solar, a powerful angelic being. The Solar does not attack unless provoked, but it will not allow passage through the portal to those it deems unworthy.

The staff remains in this form until you use an action to return it to its normal size, or until you stow it away.

Proficiency with a Quarterstaff allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Magic, spellcaster with a Strength score of 18 or higher, Versatile, Topple