छायात्मा
छाया · आत्मन्
छाया च असौ आत्मा च
कर्मधारय — a reflection, and it is a self
कर्मधारय. your reflected self — Mallinātha's vigraha is the karmadhāraya written out in full, छाया चासावात्मा च, and his gloss is प्रतिबिम्बशरीरम्, a body made of reflection. The compound is what the whole stanza turns on: not the cloud, but the cloud's image, is what the river takes in
uncheckedMallinātha, Sañjīvinī“chāyā cāsāvātmā ca | so'pi pratibimbaśarīraṃ ca praveśaṃ lapsyate”