Silk-spun child possessed by the void.
Heavy spoiler warning for Act 3 of Hollow Knight: Silksong.
Lost Lace is the void-corrupted form of Lace (Hollow Knight) and the true final boss of Hollow Knight: Silksong. She has a similar appearance as she does in Act 1 and 2, but with her entire body pitch-black. As before she wields a Pin (Hollow Knight), though she can now also summon void Tentacles and projectiles.