Valmiki Ramayana Kishkindha Kanda Sarga 57 Shloka 9
Original Shlokaते प्रायमुपविष्टास्तु दृष्ट्वा गृध्रं प्लवङ्गमाः। चक्रुर्बुद्धिं तदा रौद्रां सर्वान्नो भक्षयिष्यति।।4.57.9।।
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प्रायम् fasting unto death, उपविष्टाः seated, ते प्लवङ्गमाः those monkeys, गृध्रम् vulture, दृष्ट्वा after seeing, तदा then, नः us, सर्वान् all, भक्षयिष्यति he will eat away, रौद्रम् terribly, बुद्धिम् in their minds, चक्रुः thought .
On seeing the vulture, the monkeys fasting unto death got a terrible thought in their minds that the vulture might eat them.