Shiva Purana
अंतर्भूभिगतस्तत्र वालुकांतर्हितः स्थितः ॥ राक्षसस्य मधोः पुत्रो धुंधुनामा सुदारुणः ॥ १५ ॥
He stays underground concealed by the sand. The terrible Rākṣasa son of the demon Madhu is Dhundhu by name.
english translation
aMtarbhUbhigatastatra vAlukAMtarhitaH sthitaH ॥ rAkSasasya madhoH putro dhuMdhunAmA sudAruNaH ॥ 15 ॥
hk transliteration by Sanscript