Z-Ball (item)
The Z-Ball is used to facilitate the minigame of the same name, but also functions as a weapon. When outside of the Z-Ball minigame, bouncing the Z-Ball on the ground multiple times will cause it to enter a heated state, upon which it will damage enemies it collides with (even those that are immune to thrown weapons, it does not inflict throwing-type damage.) If the Z-Ball is allowed to sit for too long without bouncing, it will cool back down and become nonlethal, needing to be dribbled again before use.
Lore
The ball originates in the Z-Ball minigame, taking place in Zardo's dream where he is a renowned athlete and sportsman, a professional at a game also named after himself, set in the aptly named Dream Stadium. Apparently wizard dreams can manifest as tangible forms, as the climber is somehow able to physically enter Zardo's dream and compete against him, as well as take the Z-Ball out of his dream and use it anywhere in the real tower thereafter.
Obtaining
The Z-Ball can be found in Zardo's dream.