Ramayana
तेनास्य राज्ञस्तौ पादौ तदा कल्माषतां गतौ । तदाप्रभृति राजा ऽसौ सौदासः सुमहायशाः । कल्माषपादः संवृत्तः ख्यातश्चैव तथा नृपः ॥ 7-65-32 ॥
By that, the two feet of this king then became spotted; and from that time onward this king Saudasa of great renown became known as Kalmashapada, the king with the spotted foot.
english translation