A special medicinal herb placed under the tongue. When Pei Hao first placed one under young Pei Nai's tongue, it sprouted roots that burrowed deep into her flesh and merged with it, beneficial for eyesight and longevity. Ten years after Pei Nai's death, an old monk placed one under Mingzhi's tongue, reviving her after she had stopped breathing for hours. The fragment reappeared in Pei Nai's new body when she woke up.
