Srimad Bhagavatam Canto 10, Chapter 18, Text 26

SB 10.18.26

tam udvahan dharani-dharendra-gauravam
 mahasuro vigata-rayo nijam vapuh
sa asthitah purata-paricchado babhau
 tadid-dyuman udupati-vad ivambudah
As the great demon carried Balarama, the Lord became as heavy as massive Mount Sumeru, and Pralamba had to slow down. He then resumed his actual form — an effulgent body that was covered with golden ornaments and that resembled a cloud flashing with lightning and carrying the moon.
]Here the demon Pralamba is compared to a cloud, his golden ornaments to lightning within that cloud, and Lord Balarama to the moon shining through it. Great demons can assume various forms by exerting their mystic power, but when the Lord’s spiritual potency curtails their power, they can no longer maintain an artificial form and must again manifest their actual, demoniac body. Lord Balarama suddenly became as heavy as a great mountain, and although the demon tried to carry Him high on his shoulders, he could not go on.


Srimad Bhagavatam Canto 10, Chapter 18, Text 25
Srimad Bhagavatam Canto 10, Chapter 18, Text 27