Vilethorn

The Vilethorn is a weapon that unleashes a slow-moving row of thorns. The low damage dealt by the thorns is compensated by being able to hit an enemy multiple times before dissipating. The thorns pass through walls and enemies, making this weapon ideal for killing groups of monsters and the Eater of Worlds. The Vilethorn has a chance to drop from a destroyed Shadow Orb. It can also be found by killing the Eater of Worlds as a rare drop.

A good tactic is to use the Vilethorn with a full set of Meteor Armor and 2-3 Band of Starpowers which ensures that your mana regenerates faster than you can use it up, this is especially useful for the Eater of Worlds boss fight.