Valmiki Ramayana Kishkindha Kanda Sarga 50 Shloka 17
Original Shlokaइत्युक्त्वा तद्बिलं सर्वे विविशुस्तिमिरावृतम्।।4.50.17।। अचन्द्रसूर्यं हरयो ददृशू रोमहर्षणम्।
1 source checked for this shloka
इति thus, उक्त्वा having been told, सर्वे all, तिमिरावृतम् filled with darkness, तत् बिलम् that cave, विविशुः entered, हरयः monkeys, अचन्द्रसूर्यम् where there is no Moon or Sun light, रोमहर्षणम् horripilating, ददृशुः saw.
On hearing him, the monkeys entered the cave full of darkness. There was no light of the Moon or the Sun. It was a horripilating experience.