He wears, well trained in magic guile, The figure of a deer a while, Bright as the very sun, or place Where dwell the gay Gandharva race. No deer, O Ráma, e’er was seen Thus decked with gold and jewels’ sheen. ’Tis magic, for the world has ne’er, Lord of the world, shown aught so fair.”

In plain words: Lakshmana says Maricha is skilled in magic and takes the shape of a deer. No real deer has ever shone with gold and jewels like this, so it must be magic.