In Hinduism, the Karanodaka^[1][2] (IAST: Kāraṇodaka) or the Garbhodaka (IAST: garbhodaka), also referred to as the Causal Ocean, is the origin of material creation. It is the place in the spiritual sky where Mahavishnu lies down and creates the material world.^[3][4] The Causal Ocean is the border between the spiritual and material worlds.^[5]

The Bhagavata Purana offers the following details regarding the Causal Ocean:^[6]

Lord Maha-Vishnu is the source of thousands of avataras in His thousands and thousands of subjective portions. He is the creator of countless individual souls. He is also known by the name of Narayana, meaning the shelter of all the individual jiva souls. From Him springs forth the vast expanse of water known as the spiritual Causal Ocean wherein the material creation takes place. Maha-Vishnu then reclines in the waters of the Causal Ocean in a state of divine sleep, called yoga-nidra. Thus, it is said that the universal creation is but the dream of Maha-Vishnu.

— Bhagavata Purana

The above text also talks about this ocean with regards to the hiranyagarbha, the golden cosmic egg of creation:^[7]

When this Virāṭ Puruṣa (Brahmā), bursting open the Cosmic Egg, came out and stood apart from the Brah'māṇḍa, he pondered over a place for himself. He himself being pure, created pure water (called garbhodaka). On those waters created by Him, he lay for a period of a thousand years. Waters were created by the Man (nara) [and hence came to be called nārā] He is called Nārāyaṇa (as nārā or waters were his ayana ‘place of abode’).

— Bhagavata Purana, Chapter 10

Mahavishnu is described to lie down in the Causal Ocean. The water of the Causal Ocean is also referred to as the Karana Ocean, and is regarded as wholly spiritual since it originated from the body of Mahavishnu. The sacred Ganga is mentioned to have its source from this ocean, stated as the reason for its purifying effect. Balarama is described to expand into the great serpent known as Shesha. He is stated to repose on the Causal Ocean. He serves as the bed upon whom Vishnu reclines. The serpent is also stated to serve as the deity's paraphernalia, including such items as the umbrella, slippers, bedding, pillow, garments, resting chair, residence, the sacred gayatri thread, as well as his throne. During the time of creation, after Vishnu is described to have been sleeping for a while, the first emanations from the breathing of this deity are the personifications of the Vedas, who awake him from his slumber.^[8]

The Dashavatara Stotram mentions the Garbhodaka ocean:^[9]

vasati dasana-sikhare dharani tava lagna

sasini kalanka-kaleva nimagna kesava dhrta-sukara-rupa jaya jagadisa hare

O Kesava! O Lord of the universe! O Lord Hari, who have assumed the form of a boar! All glories to You! The earth, which had become merged in the Garbhodaka Ocean at the bottom of the universe, sits fixed upon the tip of Your tusk like a spot upon the moon.

— Dashavatara Stotram

• Garbhodaksayi Vishnu