Ball is the original stamina bit of the generation, arriving with BX-03 and the first Wizard Arrow. It is a plain hemispherical plastic tip, smooth, with a fairly broad contact patch against the stadium floor. That width gives it a controllable circular movement pattern rather than a true stationary spin — it drifts in wide, lazy loops that stay in the middle of the dish, which is often enough to slip out from under an early attack strike. Hard-launched it can wander far enough to catch the X-Line, which is the main way a Ball combo loses a match it should have won.
Competitively it is the reference point. Ball matches the raw stamina of the low-friction needle bits but without their habit of tilting over and wobbling out early, and that reliability is why it ends up under an enormous share of stamina combos in tournament decks. Wizard Rod on Ball became the combination everyone else built to beat.
It pairs with essentially anything that wants to outlast rather than outhit, and there is rarely a reason to swap away from it — players trade ratchets around Ball, not the other way round.