Srimad Bhagavatam Canto 09, Chapter 09, Text 25

SB 9.9.25

raksasam bhavam apannah
 pade kalmasatam gatah
vyavaya-kale dadrse
 vanauko-dampati dvijau
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Saudasa thus acquired the propensity of a man-eater and received on his leg a black spot, for which he was known as Kalmasapada. Once King Kalmasapada saw a brahmana couple engaged in sexual intercourse in the forest.
Srimad Bhagavatam Canto 09, Chapter 09, Text 23-24
Srimad Bhagavatam Canto 09, Chapter 09, Text 26-27