Shiva Purana

siva.sh/siva-purana/kotirudra-samhita/21/43

इति संप्रार्थितश्शंभुः सर्वान्रक्षोगणान्प्रभुः ।। हुंकारेणैव चास्त्रेण भस्मसात्कृतवांस्तदा ।। ४३ ।।

sanskrit

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