This verse is from Srimad-Bhagavatam (10.18.24). When all the cowherd boys were playing in the forest of Vrndavana, the demon Pralambasura appeared to kidnap Krsna and Balarama. The asura appeared disguised in the form of a cowherd boy, but Krsna could understand his trick. Krsna therefore divided all the cowherd boys into two parties. One party belonged to Balarama, and the other party belonged to Krsna Himself. Ultimately Krsna was defeated in this play, and according to the wager, the defeated party had to carry the victorious party on their shoulders. Krsna had to carry Sridama on His shoulders, and Bhadrasena had to carry Vrsabha. The demon Pralambasura had to carry Balarama, and when Balarama mounted his shoulders, the demon ran far away. Finally the demon began to expand his body to a gigantic size, and Balarama understood that he intended to kill Him. Balarama immediately struck the demon's head with His strong fist, and the demon fell down dead as if he were a snake whose head had been smashed.