This blade seems to flicker in and out of existence but always strikes true. You gain a +1 bonus to attack and damage rolls made with this magic weapon, and you can choose for its attacks to deal force damage instead of piercing damage. As an action while holding this sword or as a reaction when you deal damage to a creature with it, you can turn incorporeal until the start of your next turn. While incorporeal, you can move through other creatures and objects as if they were difficult terrain. You take 1d10 force damage if you end your turn inside an object.