nirīkṣya tad-vapur alam ambare carat
pradīpta-dṛg bhru-kuṭi-taṭogra-daḿṣṭrakam
jvalac-chikhaḿ kaṭaka-kirīṭa-kuṇḍala-
tviṣādbhutaḿ haladhara īṣad atrasat
nirikshya -- seeing; tat -- of Pralambasura; vapuh -- the body; alam -- quickly; ambare -- in the sky; carat -- moving; pradipta -- blazing; drik -- his eyes; bhru-kuti -- of his frown upon his eyebrows; tata -- on the edge; ugra -- terrible; damshtrakam -- his teeth; jvalat -- fiery; sikham -- hair; kataka -- of his armlets; kirita -- crown; kundala -- and earrings; tvisha -- by the effulgence; adbhutam -- astonishing; hala-dharah -- Lord Balarama, the carrier of the plow weapon; ishat -- a little; atrasat -- became frightened.
Srila Sanatana Gosvami explains Lord Baladeva's so-called fear as follows: Balarama was playfully acting out the role of an ordinary cowherd boy, and to maintain the mood of this pastime He appeared slightly disturbed by the horrible demoniac body. Also because the demon had appeared as a cowherd boyfriend of Krishna's and because Krishna had accepted him as a friend, Baladeva was slightly apprehensive about killing him. Balarama could also have been worried that since this cowherd boy was actually a demon in disguise, at that very moment another such demon might have been attacking Lord Krishna Himself. Thus the omniscient and omnipotent Supreme Lord Balarama exhibited the pastime of becoming slightly nervous in the presence of the horrible demon Pralamba.