Saudāsa thus acquired the propensity of a man-eater and received on his leg a black spot, for which he was known as Kalmāṣapāda. Once King Kalmāṣapāda saw a brāhmaṇa couple engaged in sexual intercourse in the forest.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
राक्षसं भावमापन्नः पादे कल्माषतां गतः । व्यवायकाले ददृशे वनौकोदम्पती द्विजौ
rākṣasaṃ bhāvamāpannaḥ pāde kalmāṣatāṃ gataḥ | vyavāyakāle dadṛśe vanaukodampatī dvijau
SB 9.9.25