So by that matchless arrow cleft, The deer’s bright form Márícha left, Resumed his giant shape and size And closed in death his languid eyes. When Ráma saw his awful foe Gasp, smeared with blood, in deadly throe, His anxious thoughts to Sítá sped, And the wise words that Lakshmaṇ said, That this was false Márícha’s art, Returned again upon his heart.

In plain words: Struck by the arrow, Maricha leaves the deer shape, returns to his giant demon form and dies. Seeing him bleeding, Rama thinks of Sita at once. He remembers Lakshmana's warning that the deer was Maricha's trick.