Wondrous item, uncommon (requires attunement)
Aside from being carved from bone, this comb is a beautiful example of functional art. It has 3 charges. As an action, you can expend a charge to cast invisibility.
Unlike the standard version of this spell, you are invisible only to undead creatures. But you can attack creatures who are not undead (and thus unaffected by the spell) without ending the effect. Casting a spell breaks the effect as normal. The comb regains 1d3 expended charges daily at dawn.