Skandapurana 5.59.25

5.59.25

tatastatsiddhidaṃ jñātvā liṃgaṃ vai pākaśāsanaḥ ..
pāṃsubhiḥ pūrayāmāsa yathā kaścinna budhyate .. 25 ..

Then, knowing that liṅga to be a bestower of perfection, Indra (Pākaśāsana) / covered it with dust so that no one would know of it.