Rainbow Body

 The Sufi call it "the most sacred body" and the "supra-celestial body". Taoists call it "the diamond body", and those who have attained it are called "the immortals" and "the cloud walkers".  Tantric yoga - "the divine body",  Kriya yoga  - "the body of bliss",  Zoroastrian Vendanta - "the superconductive body", Gnosticism  - "the radiant body", Mithraic liturgy  - "the perfect body",  Hermetic Corpus - "the immortal body" and "the Golden Body" in Emerald Tablets. Certainly, it not always the same identical concept but it concerns a supreme level of realization when the yogi dissolves the physical body. Sometimes, that is occurs the apparent dematerialization and transmutation of the physical body to some mystical luminescence. Possible to think that it's just mythology but mysterious stories of luminosity or saintly radiance are common among Buddhist mystics, Christian saints, Sufis, Taoist sages, Hindu yogis and Tirthankaras of Jainism. Especially in Dzogchen tradition of Tibetan Buddhism, where Parinirvana and Mahasamadhi are refined sometimes into Rainbow Body. It is depicted by the five rainbow colors, or the Five Pure Lights.

This "rainbow light" is not material light. It is the natural energy of the primordial state and the cause of samsara and nirvana. Through the movement of this pure light, which is the inner rigpa energy in the dimension of the primordial base, the five pure lights develop and begin to appear.
But what we can see? In philosophical sense, for the deluded, only rough matter seems to appear. It includes classical elements, namely: space, air, water, fire, earth. Conditionally, each element has own colour.

Blue symbolises sky/space

White - air/wind

Red - fire

Green - water

Yellow - earth

The Five Pure Lights are the most subtle dimension of these five elements. Interesting that Tenzin Wangyal holds that the Five Pure Lights become the Five Poisons if we remain deluded, or the Five Wisdoms if we recognize their purity. So, in this connection, it is also Buddhist correspondence of five Lights to five knowledge-wisdom levels -  pañca-jñāna:
Ādarśa-jñāna - Melong, mirror-like awareness
Samatā-jñāna - Awareness of sameness, the non-dual method of upāya and prajñā
Pratyavekṣaṇa-jñāna - Investigative awareness
Kṛty-anuṣṭhāna-jñāna - Accomplishing activities, spontaneously
Tathatā-jñāna - Suchness, dharmadātu, universal substrate

But all this is philosophical interpretation and, after all, the mystical phenomenon is not subject to it. It is awareness itself and is dependent on nothing else. Despite of different definitions - as the body of Light, or alchemical transmutation, or rainbow body - it represents a complete, total and radical transformation of one's status of being, therefore, while we still here we cannot understand it. After all, all colors of the rainbow are an outcome of One Light. As Siddhar Sage Vallalar, who was mystically dissolved also, has left some words to us

Arut Perum Jyothi - Supreme Grace Light

Tanip Perung Karunai  - Pour down upon us