Blue Moon

Blue Moons are Flails that can be found in dungeons. When used, it will emit light around it. This flail is stronger than the Ball 'O Hurt but weaker than the Sunfury.

When the ball goes too far from the player or hits a block, it quickly retracts. Like boomerangs and other flails, throwing the weapon behind a line of enemies will force it to retract through them all, dealing damage to every one of them. This is especially effective in dealing with Goblins, clumps of enemies, and large enemies.

This video shows the Blue Moon in action against the Eater of Worlds. It's particularly useful against this boss (as well as bone serpents) because it can go through them and hit all of their parts at the same time: