1. There seems to be a few mods that if added to a Boomerang break the Mystic Arc special move, hit area effects being one of the most noticeable offenders. These broken Boomerangs will let you "activate" the move but no mana is spent and nothing happens. Hit Fatigue was another mod I stumbled on that breaks this move and there are probably more. 2. If you manage to avoid certain mods and make a Boomerang that works then Mystic Arc is also applying it's effect in the wrong order. According to the moves intention it is suppose to hit the primary target for full force with a chaos damage explosion and the secondary target for half the damage of the first target. Currently it is the opposite of this, making it a very poor choice against your priority target, and even more so against a solo mob. You are also probably aware that moves like Concussion Blow, the Boomerang's secondary don't play well with damage bonuses like Slayers, etc... this leaves the Boomerang in poor shape for most situations. For a weapon that is so rarely used it's an unfortunate situation. Lastly I would also just like to mention that when reforging the Boomerangs on Test Center with Vicious/of Slaughter I was unable to get any other mod from Vicious/of Slaughter except HCI. It seemed like it wasn't recognizing the other mods from the category at all, and this was after 100's of charges with the varying hammers that let you select the property. (Up to Gold.) Just pointing this out as well in case it's unintended, it certainly was a tedious experience.