Valmiki Ramayana Yuddha Kanda Sarga 58 Shloka 55
Original Shlokaसातेनकपिमुख्येनविमुक्तामहतीशिला । बिभेदबहुधाघोराप्रहस्तस्यशिरस्तदा ।।6.58.55।।
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सातेन by that, तेनकपिमुख्येन by the foremost of Vanaras, विमुक्ता hurled, महती huge, घोरा dreadful, शिला rock, प्रहस्तस्य Prahastha's, शिरः head, बहुधा many pieces, बिभेद broken.
Hurled by Neela, the foremost of monkeys, the huge rock broke the head of Prahastha into pieces.