Verse 17

अप्रेक्ष्यमाणा स्फुरति प्रेक्षिता सु विनश्यति ।मायेयमपरिज्ञायमानरूपैव वल्गति

In plain words

Unwatched, it flashes forth; closely watched, it utterly perishes. This māyā, its very form never fully known, goes leaping and frisking about.