Canto 2 -
Ayodhyā-kāṇḍa
Chapter 63: Daśaratha Remembering Killing a Sage’s Innocent Son
Text 2.63.18

पतितेनाम्भसा च्छन्नः पतमानेन चासकृत्।
आबभौ मत्तसारङ्गस्तोयराशिरिवाचलः॥

patitenāmbhasā cchannaḥ patamānena cāsakṛt
ābabhau matta-sāraṅgas toya-rāśir ivācalaḥ

patitena = that had fallen; ambhasā = with the rain water; channaḥ = covered; patamānena = that were falling; ca = and; asakṛt = constantly; ābabhau = shone; matta-sāraṅgaḥ = a furious elephant 1; toya-rāśiḥ = ocean; iva = like; acalaḥ = a waveless.

Covered with the rain water that had fallen and that were constantly falling, a furious elephant shone like a waveless ocean.

Acalaḥ can also mean “mountain” and hence indicates that the elephant shone like a mountain [filled with water].