kṛṣṇa-bahirmukha haṣā bhoga-vāṣchā kare nikaṭa-stha māyā tāre jāpaṭiyā dhare

(Prema-vivarta)

Because of his desire to enjoy the material world, the living entity is dressed with the material gross and subtle bodies. Thus he is given a chance to enjoy the senses. The senses are therefore the instruments for enjoying the material world; consequently the senses have been described as friends. Sometimes, because of too much sinful activity, the living entity does not get a material gross body, but hovers on the subtle platform. This is called ghostly life. Because of his not possessing a gross body, he creates a great deal of trouble in his subtle body. Thus the presence of a ghost is horrible for those who are living in the gross body. As stated in Bhagavad-gītā (15.10) :

utkrāmantaṁ sthitaṁ vāpi bhuṣjānaṁ vā guṇānvitam vimūḍhā nānupaśyanti paśyanti jṣāna-cakṣuṣaḥ

“The foolish cannot understand how a living entity can quit his body, nor can they understand what sort of body he enjoys under the spell of the modes of nature. But one whose eyes are trained in knowledge can see all this.”

The living entities are merged into the air of life, which acts in different ways for circulation. There is prāṇa, apāna, udāna, vyāna and samāna, and because the life air functions in this fivefold way, it is compared to the five-hooded serpent. The soul passes through the kuṇḍalinī-cakra like a serpent crawling on the ground. The life air is compared to uraga, the serpent. Paṣca-vṛtti is the desire to satisfy the senses, attracted by the five sense objects, namely form, taste, sound, smell and touch.