Shiva Purana
इति संप्रार्थितश्शंभुः सर्वान्रक्षोगणान्प्रभुः ॥ हुंकारेणैव चास्त्रेण भस्मसात्कृतवांस्तदा ॥ ४३ ॥
Thus requested, lord Śiva reduced the Rākṣasa to ashes with only a Huṃ sound for hīs weapon.
english translation
iti saMprArthitazzaMbhuH sarvAnrakSogaNAnprabhuH ॥ huMkAreNaiva cAstreNa bhasmasAtkRtavAMstadA ॥ 43 ॥
hk transliteration by Sanscript