Flairon

The weapon carries two shapes and you switch between them with the activate key rather than by attacking. In one shape it behaves like a classic thrown flail: hold the button and it circles you, let go and it drops to the floor. In the other it launches straight out like a harpoon and snaps back the instant it clips an enemy or a wall, or once the chain runs out of slack. Both shapes trail homing bubbles the entire time they are out.

Landing the ball itself is close to irrelevant. The damage comes from bubble volume, and bubbles only appear while the flail is deployed, so playing it well is entirely about keeping the thing in the air longer. Throw it away from your target and walk in the other direction. The chain stretches, the stream keeps coming, and the bubbles curve back toward whatever is nearest without your help. Aiming precisely is the beginner mistake, because a clean hit retracts the flail and cuts the stream short.

Bubbles lock on from a long way off, get a single bounce off solid ground, and pop shortly after, so tight corridors let them ricochet into things you never lined up. They do not pierce, which means a packed crowd eats them one enemy at a time while a single fat target is where the weapon looks best. They also carry on-hit effects, which is unusual for a secondary projectile. Imbuement flasks, a Magma Stone and the Frost Breastplate set bonus all apply through them, and at that rate of fire the debuff never lapses. Water slows the flail like any other projectile, and here that is a gain rather than a loss, since a lazier return means more time deployed.

It falls from Duke Fishron, so it arrives whenever you decide to pick that fight, which can be absurdly early if you are stubborn. Godly and Demonic land in the same place on average, so keep whichever rolls first. The name mashes flail with Fishron, the launcher form mashes that again with harpoon, and Re-Logic has slipped and written it as Flailron in its own patch notes. Only two other flails throw extra projectiles at all, the Flower Pow and the Drippler Crippler.