Ruler

For several versions this was an accessory that drew alignment lines on screen while you built, and nothing else. That job moved out to the Mechanical Ruler and eventually into The Grand Design, and what was left behind got repurposed as a shortsword. If you went looking for a measuring aid and bought this, you bought the wrong item.

One use is a flurry of quick stabs at slightly different angles, so it looks far busier than it hits. Invincibility frames cap how often a single enemy can take damage, and the swing rate is fast enough that roughly half the stabs land on a target that is still flashing. Against a crowd, where the stabs spread across several bodies, it does better than the raw numbers suggest. It is cheap, it comes from an NPC rather than a drop, and that is most of its appeal.