Valmiki Ramayana Sundara Kanda Sarga 42 Shloka 37
Original Shlokaतस्य सन्नादशब्देन तेऽभवन्भयशङ्किताः। ददृशुश्च हनूमन्तं सन्ध्यामेघमिवोन्नतम्।।5.42.37।।
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ते they, तस्य his, सन्नादशब्देन with the sound of hearing, भयशङ्किता: errified, अभवन् seemed, सन्ध्यामेघमिव like a cloud in twilight, उन्नतम् towering, हनूमन्तम् Hanuman, ददृशुश्च saw.
Terrified on hearing the roar, the kinkaras looked at the towering Hanuman who seemed like a cloud in twilight (red in colour).