Ball O' Hurt

The head stays out while the button is down and drags through whatever it touches, so the damage comes from parking it inside something rather than from clean individual hits. That takes adjusting to if you have been swinging swords, and it is why the weapon feels weak for the first minute and much better after ten.

A worm is a column of segments that each take damage on their own, so a weapon that lingers inside the body chews several at once. Against the Eater of Worlds that turns a long grind into a short fight, and it is the quickest kill most players have available at that stage of a corruption world.

Crimson worlds pull The Meatball out of hearts instead and it behaves the same way. Neither one is a sure thing from a single Shadow Orb, so if the orbs are being stingy, keep breaking them or fish up corrupt crates and open those instead.