Scourge of the Corruptor

Nothing drops this and you cannot build it. It sits in the Corruption Chest in the Dungeon, which stays shut until you feed it a Corruption Key, and keys do not start appearing in corruption enemy loot until Plantera is dead. So it is a post-Plantera pickup with a farming step in front of it, and the chest holds exactly one, so there is no rolling for a better copy.

The javelin bursts on terrain just as happily as it bursts on a body. Fire at the ground or a wall near whatever you are fighting and every throw becomes a cloud of homing eaters that go and find it for you. That turns a weapon you would otherwise have to lead into one you can use while sprinting backward, which is why it holds up in fights where standing still gets you flattened.

How many eaters a throw produces is rolled fresh each time, and there is a rare result that empties a huge batch at once, so your damage arrives in lumps rather than a steady stream. They also drift for a beat before they begin seeking, and they only look for something within roughly fifty tiles. At point blank range against a fast mover, a few will simply wander off before they lock. Once they do lock they accelerate hard, and they get triple the acceleration when they are moving the wrong way, so a bad initial heading corrects quickly. They will also drop their target for a closer one mid flight.

Each one bounces a few times before it gives up, and they cover an enormous distance, so a swarm fired in the right general direction usually finds work. While they are not homing they pass straight through critters, cobwebs and target dummies, which means dummy testing badly underreads what this weapon actually does. Against worms and packed events they reach segments and bodies you would never connect with by hand.

Vampire Knives come out of the equivalent chest on a crimson world, and they heal you while you fight. This does not heal anything. On a corruption world you are trading sustain for reach and tracking, which hurts a melee player's survivability and helps enormously in fights where closing the distance is what kills you.

A scourge is normally a multi-tailed whip, and this is not one. The tooltip calls it a javelin. The other reading of the word, something that brings misery, is the one that fits. It also has no special edge against Corruptors and none of them drop it.