Valmiki Ramayana Aranya Kanda Sarga 42 Shloka 14
Original Shlokaस रावणवचश्श्रुत्वा मारीचो राक्षसस्तदा। मृगो भूत्वाऽश्रमद्वारि रामस्य विचचार ह।।3.42.14।।
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तदा then, सः that, राक्षसः demon, मारीचः Maricha, रावणवचः Ravana's words, श्रुत्वा on hearing, मृगः deer, भूत्वा transformed, रामस्य Rama's, आश्रमद्वारि at the entrance of the hermitage, विचचार ह started moving.
Hearing Ravana's words, Maricha transformed himself into a deer and started moving at the entrance of Rama's hermitage.