The Universal form of Krsna is described in the Bhagavad-Gita as having unlimited heads, hands, and legs. Arjuna saw that some of such heads were eating the soldiers on both armies, and some were even being crushed amongst their teeth. Although the Universal form included both beautiful and terrible manifestations, the mind of Arjuna seemed to be more affected by such ghastly scenes, as described in the Bhagavad-Gita.
The Universal form is also described in the second canto of Srimad Bhagavatam as an imaginary form that is used by yogis coming from impersonalism to adjust to the idea that God has a form. Since they can’t directly see the spiritual form of Krsna at this stage, they are recommended to meditate on different aspects of the material universe as parts of this gigantic universal form.
In the first chapter of the 2nd canto of Srimad Bhagavatam, for example, it’s mentioned: “His arms are the demigods headed by Indra, the ten directional sides are His ears, and physical sound is His sense of hearing. His nostrils are the two Aśvinī-kumāras, and material fragrance is His sense of smell. His mouth is the blazing fire. The sphere of outer space constitutes His eyepits, and the eyeball is the sun as the power of seeing. His eyelids are both the day and night, and in the movements of His eyebrows, Brahmā and similar supreme personalities reside. His palate is the director of water, Varuṇa, and the juice or essence of everything is His tongue.”
Do the universal form, as described in the Srimad Bhagavatam really exist? Yes and no. It exists in the sense that the universe exists, and everything is related to Krsna for being part of His energy. On the other hand, the universal form described in the Srimad Bhagavatam is imaginary in the sense that Krsna doesn’t have a material form. The form the yogis meditate upon is thus more or less imaginary, conceived to foment their spiritual understanding.
How does this relate to the universal form shown to Arjuna (and others) in the Bhagavad-Gita?
When Arjuna asked Krsna to see His Universal form, Krsna answered: “you cannot see Me with your present eyes. Therefore I give you divine eyes. Behold My mystic opulence!”
The transcendental eyes given by Krsna allowed Arjuna to see, from the seat in his chariot, everything that exists in the universe as well as past present, and future from the location. The many different forms Arjuna saw were the forms of the different demigods, demons, and other powerful beings. All these beings are empowered by Krsna to execute their activities, therefore they are part of the Lord’s Universal body. Arjuna’s vision of the universal form devouring the soldiers in both armies where a vision of how the forces of time would crush them in a near future. Time is an inexorable force that wears out and eventually destroys everything. Everyone in this material world is eventually devoured by time.
Imagine you could see everything that happened and will happen in the history of the universe simultaneously. This would certainly be a simultaneously wonderful and terrifying experience. Imagine reviving all the horrors of all the different wars that happened and will happen in the future, as well as the individual joy and suffering of each person who lived or will live in the universe.
Being a devotee, Arjuna immediately connected everything he saw with Krsna, understanding that everything that exists is a manifestation of Krsna’s energy. However, he couldn’t check the feelings that came from such a vision. In this way, his natural relationship of friendship with Krsna was temporarily replaced with a feeling of fear and veneration, in which Arjuna offered prayers. Krsna then showed him His four-armed form as Narayana and finally assumed again His original form with two hands.
The display of the universal form as well as the four-handed form of Narayana form serves as proof of the divinity of Krsna. As Srila Prabhupada mentions, it set the standard for anyone claiming to be an incarnation. If someone claims to be an incarnation of God and is not capable to show his universal form, he should immediately be rejected as a fraud.
The universal form described in the Srimad Bhagavatam is thus not exactly the same as the form shown to Arjuna. Yogis use their minds and intelligence to try to conceive an imaginary form composed of the different material manifestations encased inside the universe. The level of detail they can conceive will vary according to their intellectual power, but the form remains a product of their imagination. Arjuna on the other hand could directly see everything that exists using the transcendental eyes given to him by Krsna.