Mahabharata 7.121.24

सोऽयं तप्यति तेजस्वी तपो घोरं दुरासदम्समन्तपञ्चकादस्माद्बहिर्वानरकेतन

so'yaṃ tapyati tejasvī tapo ghoraṃ durāsadamsamantapañcakādasmādbahirvānaraketana

Our plain-language meaning of this verse is waiting for scholar review.