Valmiki Ramayana Sundara Kanda Sarga 1 Shloka 182
Original Shlokaप्लवमानं तु तं दृष्ट्वा सिंहिका नाम राक्षसी। मनसा चिन्तयामास प्रवृद्धा कामरूपिणी।।5.1.182।।
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कामरूपिणी who can take any form at will, सिंहिका नाम called Simhika, राक्षसी demoness, प्लवमानम् him who was speeding in the sky, तम् him, दृष्ट्वा after seeing, प्रवृद्धा expanded in size, चिन्तयामास started thinking.
Seeing Hanuman speeding in the sky a demoness called Simhika who can assume any form at her will had grown out of proportion and thought on her part: