Back Stabber

The Back Stabber is a Hardmode broadsword that is dropped by Mister Stabbies during the Frost Legion event. Striking the back side of an enemy with this weapon guarantees that it will critically strike for 400% damage. It also decreases the chance for enemies to target you and has autoswing.

Trivia

 * The Back Stabber and its mechanics are a reference to the video game, in which the Spy can attack with a "backstab", resulting in an instant kill against the enemy.